List of articles (by subject)
-
Open Access Article
1 - Effect of Heat Treatment and B4C Carbide Distribution on Corrosion and Wear Resistance of Ni-P/Ni-B-B4C Double Layer Coating
محسن رضاقلی زاده اعظم حیذری احمد ساعتچی -
Open Access Article
2 - Numerical simulation of thermal plasma spray
علی رضا گنجوئی -
Open Access Article
3 - The effect of surface mechanical attrition treatment time on corrosion behavior of pure Copper
بهروز شایق بروجنی احسان اکبری خراجی -
Open Access Article
4 - Investigation of Corrosion Inhibition of Two Thiazole Derivatives for AISI Steel Alloy in HCl Solution
ایمان دانایی Alireza Hoseizadeh Mohammad Hossein MaddahyIn most industrial processes, acidic solution are commonly used for the pickling, industrial acid cleaning, acid descaling, oil well acidifying, etc. Corrosion prevention systems favor the use of corrosion inhibitors with low or zero environmental impacts. In this work, MoreIn most industrial processes, acidic solution are commonly used for the pickling, industrial acid cleaning, acid descaling, oil well acidifying, etc. Corrosion prevention systems favor the use of corrosion inhibitors with low or zero environmental impacts. In this work, the inhibition ability of 2-Mercaptobenzothiazole (MBT) and 2-amino-5-nitrothiazole (Nitramine) (two thiazole derivatives) against the corrosion of AISI steel 4130 in 1 M HCl solution were evaluated by polarization and electrochemical impedance spectroscopy (EIS). Polarization studies indicated that MBT retards both the cathodic and anodic reaction and Nitramine retards anodic reaction through chemical adsorption and blocking the active corrosion sites. EIS data was analyzed to equivalent circuit model shows that as the inhibitor concentration increased the charge transfer resistance of steel increased whilst double layer capacitance decreased. Thermodynamic parameters such as activation energy, enthalpy, entropy and free energy of adsorption were calculated and Atomic force microscopy (AFM) was used to study the steel surface with and without inhibitors. Manuscript profile -
Open Access Article
5 - The effect of temperature and concentration of sulfuric acid on the concrete crown corrosion
محمد آقابابایی بنی محمود پاکشیرIt`s impossible to overhaul the sewer collection lines, or remove sewer lines from the sewage system. As a result, the necessary studies should be performed to identify appropriate strategies to prevent blockage of the pipes. One of the common problems in the field is c MoreIt`s impossible to overhaul the sewer collection lines, or remove sewer lines from the sewage system. As a result, the necessary studies should be performed to identify appropriate strategies to prevent blockage of the pipes. One of the common problems in the field is crown corrosion due to the presence of sulfuric acid. In this study, the production of sulfuric acid in the presence of microbiological agents in pipes’ crown has been studied and the effect of environmental parameters such as temperature and acid concentration on the rate of the biological crown corrosion were investigated. For this purpose, concrete samples of the type 5 of cement used in accordance with the ASTM C150 and ASTM C595 standards, and then they were exposed to the different temperatures and concentrations of sulfuric acid. The results of the weight loss indicate that the increases in the temperatures and concentrations of acid would be led to higher corrosion rates. Finally, optical microscopic investigations and XRD analysis of the corroded sample showed that the corrosion product is ettringite. Manuscript profile -
Open Access Article
6 - The Investigation of Sensitization Effect on the Corrosion Behavior of SAF 2205 Duplex SS at Transpassive Region
خشایار مرشدبهبهانی پوریا نجفی سیار محمود پاکشیرIn this study, intergranular corrosion (IGC) behaviour of SAF 2205 duplex stainless steels (DSS) was investigated in the "2M H2SO4 + 1M HCl" solution at 30 ◦C using potentiodynamic polarization, DLEPR, X-ray diffraction, electrochemical impedance spectroscopy (EIS) and MoreIn this study, intergranular corrosion (IGC) behaviour of SAF 2205 duplex stainless steels (DSS) was investigated in the "2M H2SO4 + 1M HCl" solution at 30 ◦C using potentiodynamic polarization, DLEPR, X-ray diffraction, electrochemical impedance spectroscopy (EIS) and cyclic polarization tests. The EIS test results of the specimens, with various degrees of sensitization for 1 h and 5 h at 725 oC, shows three different responses in the trans passive region depending on the applied DC bias. Moreover, the results indicate that the charge transfer and polarization resistance (Rct and RP) of the sensitized DSS specimens decrease as a result of increasing the sensitization time which is in accordance with the optical and SEM micrographs from the corroded samples surfaces. Manuscript profile -
Open Access Article
7 - Applying Nanocomposite Ni-B-ZrO2 Coating By Electroless Method on Steel CK45 and Study its Tribological Properties
yaser zakery nia Reza Bazargan LariElectroless nickel boron coatings usually due to wear and corrosion resistance that is well regarded. Electroless nickel boron through the chemical reduction of nickel ions on the surface of the catalytic caused and controlled until the solution is in contact with the r MoreElectroless nickel boron coatings usually due to wear and corrosion resistance that is well regarded. Electroless nickel boron through the chemical reduction of nickel ions on the surface of the catalytic caused and controlled until the solution is in contact with the reaction continues. In this study, Ni-B-ZrO2 nano composite coating was made by adding 4 g⁄l of ZrO2 nano particles to nickel – boron electroless solution on samples of CK45 steel; Then the coated samples heat treated for one hour at 400℃. The morphology and chemical compound was examined using SEM equipped by EDX. Electrochemical corrosion behavior of coatings in 3.5 showed by adding ZrO2nano particles the corrosion resistant of coatings improves. Electrochemical impedance spectroscopy showed that the coating after the heat treatment hadn't a protective effect And substrate are vulnerable to corrosion. Abrasion behavior by pin on disk test was measured at ambient temperature and Vickers hardness was measured by a micro hardness testing machine devices. The results showed that adding zirconia nanoparticles to the amount of 4g⁄l increased hardness and wear resistance of the coating. Coating composite samples of nickel - boron – zirconia without heat treatment the best results for the three parameters simultaneously high hardness, abrasion resistance and excellent corrosion resistance was good. Manuscript profile -
Open Access Article
8 - Comparison of Corrosion behavior of aluminium 6061 alloy joined by friction stir lap welding and gas tungsten arc lap welding methods
reza bazarganlari ehsan vafaIn this paper wrought aluminum sheets with thickness of 5 mm were square butt welded by friction stir lap welding (FSLW) and gas tungsten arc lap welding (GTALW) methods to campare their corrosion behavior. of the welding zone was probed by tafel polarization curve. Opt MoreIn this paper wrought aluminum sheets with thickness of 5 mm were square butt welded by friction stir lap welding (FSLW) and gas tungsten arc lap welding (GTALW) methods to campare their corrosion behavior. of the welding zone was probed by tafel polarization curve. Optical metallography (OM) and scaninig electron microscop (SEM) were used to study morphology. Energy dispersive spectroscopy (EDS) were used to analysis different zone of the welds. EDS analysis proved deposits of iron and silicon in samples. FSLW and GTALW resulted in equiaxed grains of about 5 and 18 micrometr respectively, while GTALW caused dendritic structure of the welded region. To assessment mechanical properties, micro hardness test were accure. Resistance to corrosion was greater for the FSLW grains than the GTALW structure. In both cases, susceptibility to corrosion attack was greater in the welded region than the base metal section. . microhardness of FSLW specimen were grater than GTALW specimen. Manuscript profile -
Open Access Article
9 - Evaluation of the Pitting Corrosion Behavior of Al-nano Zro2 composite Produced by Accumulative Roll Bonding (ARB) Process
سینا متین محمود پاکشیرIn this study, the pitting corrosion behaviour of Al-Nano ZrO2 Nano composites fabricated by Accumulative Roll bonding (ARB) process was investigated. Strips of 1050-aluminum alloy of length 250 mm, width of 40 mm, and thickness of 1 mm annealed at 623K in ambient atmos MoreIn this study, the pitting corrosion behaviour of Al-Nano ZrO2 Nano composites fabricated by Accumulative Roll bonding (ARB) process was investigated. Strips of 1050-aluminum alloy of length 250 mm, width of 40 mm, and thickness of 1 mm annealed at 623K in ambient atmosphere and analytical grade of ZrO2 powder with an average size of 40nm were used as raw materials. The Al-Nano ZrO2 composite was produced in 5 cycles. For electrochemical measurements, the square specimens of 10mm×10mm×1mm were cut, connected to copper wires and cold mounted. The open circuit potentials (OCP) of the specimens were measured after 24h immersion in the artificial seawater (3.5wt% NaCl), then Cyclic Polarization test were carried out at range of -0.25 / 1 v with respect to OCP and scan rate of 1mV/s. The results of Cyclic Polarization test indicated that when rolling cycles increase, the Eb and Eb-Erp decrease. The repassivation improved by decrease in Eb-Erp. SEM images represent the decrease and uniform distribution of pits on the surface of samples by increasing the rolling cycles. Manuscript profile -
Open Access Article
10 - Evaluation of anti-corrosion performance of epoxy ester coating in the presence of a new generation of hybrid pigments based on Echium amoenum extract and zinc acetate
Amirsalar Dehghani Mahdi Tabatabaei, Mahdi Vahid Abouei MehriziThe impact of hybrid organic/inorganic pigments based on the herbal extract of Echium amoenum and zinc acetate on the corrosion protection performance of epoxy ester coating was investigated in this paper. The electrochemical impedance spectroscopy (EIS) measurement sho MoreThe impact of hybrid organic/inorganic pigments based on the herbal extract of Echium amoenum and zinc acetate on the corrosion protection performance of epoxy ester coating was investigated in this paper. The electrochemical impedance spectroscopy (EIS) measurement showed that the presence of hybrid pigment can expressively prevent the corrosion of steel in saline solution. The results of scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), visible ultraviolet (UV-Vis) spectroscopy and static contact angle proved the formation of chelates and protective complexes in the pigment structure. The inhibition efficiency of 89.3% shows the same point. The low-frequency impedance value of epoxy coating increased in the absence and presence of the hybrid pigment from 344 MΩ cm2 to 6056MΩ cm2. This parameter was calculated after 45 days for the blank coating and the one containing pigment 4.2 MΩ cm2 and 200 MΩ cm2, respectively, which indicates the role of pigment in increasing the barrier performance of the coating. Increasing the overall resistance values equivalent to 16343 Ω.cm2 in the epoxy coating containing pigments with synthetic scratches shows the active inhibitory role of hybrid pigments. Manuscript profile -
Open Access Article
11 - The effect of silicon doping on the mechanical and corrosion properties of tantalum carbide coating deposited by magnetron sputtering technique
Seyyed Alireza Hosseini Minasadt Emamian Mostafa AlishahiIn this study, Ta, TaC and TaSiC coatings have been deposited by a non-reactive magnetron sputtering method, and their structural, microstructural, mechanical, and corrosion properties have been investigated. XRD results revealed the presence of α-Ta and TaC0.6 ph MoreIn this study, Ta, TaC and TaSiC coatings have been deposited by a non-reactive magnetron sputtering method, and their structural, microstructural, mechanical, and corrosion properties have been investigated. XRD results revealed the presence of α-Ta and TaC0.6 phase structures in the Ta and TaC coatings, respectively. However, the TaSiC coating showed a quasi-amorphous structure. Additionally, the Ta coating showed a columnar microstructure with rough topography and tensile residual stress, while the addition of carbon and silicon resulted in the compactness and smoothness and domination compressive residual stress in the TaC and TaSiC coatings. Nanoindentation results showed that the addition of carbon to the Ta coating increased the hardness by four times, however the addition of silicon to the TaC coating had an adverse effect on the hardness of the coating. The corrosion studies revealed that the coatings have a cathodic nature with respect to the ST37 substrate, making the samples susceptible to galvanic corrosion. Furthermore, the addition of carbon and silicon was found to improve the corrosion resistance of the coatings by increasing the coating compactness and decreasing the density of open porosities. Manuscript profile -
Open Access Article
12 - Investigation of the electrochemical activity of paladium-carbon nanotubes nanocomposite toward methanol oxidation in fuel cells and comparing it with the platinium one
Roghayeh KhaleghianmoghadamIn this study, the nanocomposite of palladium-carbon nanotubes-chitosan was synthesized and characterized by XRD and TEM techniques. The synthesized nanocomposite was used for the modification of glassy carbon electrods surfaces. Using cyclic voltammetry (CV) technique, MoreIn this study, the nanocomposite of palladium-carbon nanotubes-chitosan was synthesized and characterized by XRD and TEM techniques. The synthesized nanocomposite was used for the modification of glassy carbon electrods surfaces. Using cyclic voltammetry (CV) technique, the electrochemical activity of modified electrode (GC/PdNPs-MWCNTs-CH) toward methanol oxidation was investigted in a solution of 0.5 M sodium hydroxide and 1.0 M methanol. The results revealed that the synthesized nanocomposite shows a high catalytic activity toward methanol oxidation and thus has an efficiency for use as anode for the methanol fuel cells. The effects of different parameters such as methanol and electrolyte concentrations, potential range, and potential scan reate on the anodic current density and the peak potential of methanol oxidation were also investigted. Moreover, comparing the electrochemical activity of the palladiun nanocatalyst for methanol oxidation with that of the platinum-type, it was concluded that the former has a considerable activity closed to the platinum one. Therefore, it coulde be a souitable substituer for platinum in the methonl oxidation process. This substitution, also reduces the catalyst price. Manuscript profile -
Open Access Article
13 - Coating of Steel by Long Alkyd Resin Reinforced with SiC Nanoparticles to Improve its Corrosion Resistance
Hamideh Esmaeili Sanaz Naghibi Shirin KordzangenehTo improve the properties of the organic coatings ceramic nanoparticles can be applied. In the present study, inorganic-organic nanocomposite coating contains SiC nnoparticles and alkyd resin was applied on the stainless still substrates. In this regard 1, 2 and 3 wt% o MoreTo improve the properties of the organic coatings ceramic nanoparticles can be applied. In the present study, inorganic-organic nanocomposite coating contains SiC nnoparticles and alkyd resin was applied on the stainless still substrates. In this regard 1, 2 and 3 wt% of SiC nanoparticles were used to prepare the nanocomposite. In order to achieve a homogeneous mixture of nanoparticles and polymeric resin, magnetic stirrer and ultrasonic device were used. The coatings were deposited on the substrates by dipping technique. To study the morphology thickness and surface of the coatings, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used. The corrosion resistance of the coatings was investigated by polarization Tafel test, electrochemical impedance spectroscopy (EIS) and salt spray. Corrosion test results showed a reduction of corrosion current and an increasing in the corrosion resistance of substrate with nanocomposites coating and the sample with 3 wt% nanoparticles was selected as optimum sample by reducing current density from 9/2×10-6 to 2/2×10-9. The results of adhesion test by cross-cut method showed the reduction of coating separation from 9% to 4%. The coating thickness of sample was measured about 20 μm. Manuscript profile -
Open Access Article
14 - Effect of plasma electrolytic oxidation time on the corrosion behavior of Ti-13Nb-13Zr alloy in Ringer's solution
Mahmoud Hajisafari Arman Zarebidaki amir daneshpazhouhAmong different types of Ti alloys, Ti-6Al-4V alloy has been most used in biological applications. Because of the toxicity of Al and V elements there is trend for replacing them with Ti-13Nb-13Zr alloy as a new generation of titanium alloy. In the current study plasma e MoreAmong different types of Ti alloys, Ti-6Al-4V alloy has been most used in biological applications. Because of the toxicity of Al and V elements there is trend for replacing them with Ti-13Nb-13Zr alloy as a new generation of titanium alloy. In the current study plasma electrolytic oxidation (PEO) process was used to create an oxide film on Ti-13Nb-13Zr alloy at different processing time of 1, 4, 7 and 10 minutes in a bath containing Ca and P ions at 250V. Microstructure of the specimens was studied by Field Emission Scanning Electron Microscope (FESEM). Rresults showed that the oxide film formed by PEO process contains Ti6O, Nb6O and CaHPO4 phases and increasing the time of process have no effect on the thickness of the coating. Dynamic Polarization test and time dependency of the open circuit potential was used for evaluating the corrosion behavior of the specimens in deaerated Ringer's solution. Results showed that the specimen treated for 1 minute has the lower icor and the higher Ecor (2.5×10-7 A/Cm2 and -0.12 V vs. Ag/AgCl respectively). Manuscript profile -
Open Access Article
15 - Investigation on effect of Hafnium addition on electrical and isothermal oxidation resistance of Ni-super alloy using for metallic interconnect of SOFC
dannial azimi- yancheshmeh Mohammad Esmailian Kourosh ShirvaniNi-Cr-Al-Hf alloys containing 0, 0.1, 0.2 and 0.4 wt.% Hf were produced and their isothermal oxidation behavior and electrical resistance has been investigated in air for 75 h at the temperature of 1000 °C. Microstructures of the oxidized samples were examined using MoreNi-Cr-Al-Hf alloys containing 0, 0.1, 0.2 and 0.4 wt.% Hf were produced and their isothermal oxidation behavior and electrical resistance has been investigated in air for 75 h at the temperature of 1000 °C. Microstructures of the oxidized samples were examined using scanning electron microscopy (SEM) and electrical resistance was measured. The samples showed different microstructures, and oxidation behavior depending on their chemical composition. The results indicated that the sample containing 0.4 wt.% Hf had the lowest weight gain, while the weight gain of the sample without Hf was the highest. An external scale of spinel overlying a region of internal oxides precipitates formed on Ni-12Cr-4.5Al. Conversely, an external Al2O3 formed on the samples containing Hf additions. In absence of Hf, Cr2O3 was the major scale that formed on surface. The improvement in the oxidation resistance is believed to be due to the transition between the internal and external oxidation of aluminum, adherent and protective Al2O3 oxide layer on the surface of the Ni-12Cr-4.5Al-0.4Hf alloy. It was found that the scale adhesion can be affected by mechanical keying at the alloy/scale interface resulting from the pegs’ formation during oxidation. Higher electrical resistance of Alloy without Hf is due to higher thickness of oxide scale formation on surface and sample with 0.4 wt.% Hf showed lowest electrical resistance due to thinner scale of Al2O3. Manuscript profile -
Open Access Article
16 - Application of Myrtus Extracts as a Suitable Green Inhibitor for Corrosion of Steel in HCl Solution
Mansoor Bozorg Taghi Shahrabi Farahani Fatemeh EktefaThe inhibition effect of Myrtus extract on steel corrosion in 1.0 M HCl solution was investigated by means of weight loss measurements, electrochemical polarization, electrochemical impedance microscopy and chemical quantum study. The results showed that Myrtus acts as MoreThe inhibition effect of Myrtus extract on steel corrosion in 1.0 M HCl solution was investigated by means of weight loss measurements, electrochemical polarization, electrochemical impedance microscopy and chemical quantum study. The results showed that Myrtus acts as a good inhibitor and the inhibition efficiency of this compound increases with increasing inhibitor concentration and in the presence of 1000 mg/L of the inhibitor will increase to 82%. Polarization curves showed that Myrtus extract acts as an efficient mixed type inhibitor. EIS plots indicated that the polarization resistance increased and double-layer capacitance decreased upon the addition of Myrtus to the solution. The adsorption of Myrtus on the steel surface was found to obey Temkin adsorption isotherm and the values of free adsorption energy indicate the spontaneous and chemical adsorption of inhibitors on mild steel surface. Also, quantum chemical calculations were used to correlate the adsorption of two compounds of Myrtus extract with its electronic structural parameters. Manuscript profile -
Open Access Article
17 - Effect of Tool Rotation Speed on the Mechanical Properties and Corrosion Behavior of Dissimilar Friction Stir Welded of 5083 Aluminium Alloy and Commercially Pure Titanium
Masoud Shabani بهروز شایق بروجنی رضا ابراهیمی کهریزسنگیIn this paper, the effect of tool rotation speed on the mechanical properties and corrosion behavior on dissimilar joints Friction Stir Welds between 5083 Aluminium alloy and pure Titanium is investigated. At first, with primary welding parameters range necessary to ach MoreIn this paper, the effect of tool rotation speed on the mechanical properties and corrosion behavior on dissimilar joints Friction Stir Welds between 5083 Aluminium alloy and pure Titanium is investigated. At first, with primary welding parameters range necessary to achieve suitable connection obtained and then by changing tool rotation speed, mechanical and corrosion properties of heat affected zones, welding zones and cross section zones, by using polarization Tafel test and Electrochemical Impedance Spectroscopy was investigated and the result were compared. the result indicates that corrosion behavior of connections, is impressionable of the tool rotation speed and welding zone and heat affected zones have weaker corrosion resistance compared to the base metals. Manuscript profile -
Open Access Article
18 - The effect of calcium on corrosion behavior of biodegradable Mg-5Zn-1Y Alloy
Fereshteh Dostmohamadi Hasan JafariToday, magnesium alloys as the new generation of biodegradable alloys, have attracted the attention of many researchers. In this research, the corrosion behavior of cast Mg-5Zn-1Y containing different amounts of calcium (0, 0.1, 0.5 and 1 weight percentage) was investig MoreToday, magnesium alloys as the new generation of biodegradable alloys, have attracted the attention of many researchers. In this research, the corrosion behavior of cast Mg-5Zn-1Y containing different amounts of calcium (0, 0.1, 0.5 and 1 weight percentage) was investigated. The microstructure of the alloys was analyzed using optical and scanning electron microscopes, and the corresponding phases were detected by X-ray diffraction. Corrosion behavior of cast alloys was measured using electrochemical polarization and immersion tests. Metallography analysis revealed that microstructure of the Mg-5Zn-1Y alloy includes α-Mg matrix and Mg3YZn6 lamellar phase formed at the grain boundary. The addition of calcium to the alloy refined the grains and resulted in the formation of continuous Ca2Mg6Zn3 at grain boundaries. No passive zone was detected in polarization curves, meaning domination of active polarization, indicating increased corrosion rate due to grain refinement which can be attributed to calcium addition in the alloy. The polarization and immersion tests results confirmed that the alloy Mg-5Zn-1Y-0.1Ca has the lowest corrosion rates among the investigated alloys, and the more the calcium content, the higher the corrosion rate due to the formation of cathodic Ca2Mg6Zn3 phase. Manuscript profile -
Open Access Article
19 - Investigation the Effect of Microstructure and Crystallographic Texture on the Hydrogen Induced Cracking Resistance of HSLA Steel
shahram abbasi mohammad esmailian Shahrokh AhangaraniIn this study effect of microstructure and crystallographic texture on the hydrogen induced cracking resistance of a HSLA was investigated. Samples were hot rolled between 980 to 750 °C up to 50% and quenched in different environments. Microstructure and texture of MoreIn this study effect of microstructure and crystallographic texture on the hydrogen induced cracking resistance of a HSLA was investigated. Samples were hot rolled between 980 to 750 °C up to 50% and quenched in different environments. Microstructure and texture of the samples were studied using a scanning electron microscope (SEM) equipped by electron backscattered diffraction detector (EBSD). Hydrogen induced cracking resistance of the samples were also evaluated using HIC test. Results revealed that, by increasing cooling rate more non-equilibrium phases with finer grain where formed. Grain boundary fraction also increased by increasing cooling rate which led to decrease in HIC resistance. Texture of the samples were also changed due to cooling rate enhancement furthermore texture intensity decreased. {111} // ND fiber intensity decreased due to cooling rate increase which led to decrease in intergranular crack propagation and consequently decrease in HIC resistance. Manuscript profile -
Open Access Article
20 - Corrosion behavior of magnetron sputtered tantalum coating
Mostafa Alishahi Farzad Mahboubi Seyed Mohammad Mousavi KhoieIn this study, tantalum (Ta) thin film was deposited on Si(100) and 316L stainless steel (SS) substrates by DC magnetron sputtering. The structural properties of Ta film were investigated by X-ray diffraction analysis. In addition, the scanning and transmission electron MoreIn this study, tantalum (Ta) thin film was deposited on Si(100) and 316L stainless steel (SS) substrates by DC magnetron sputtering. The structural properties of Ta film were investigated by X-ray diffraction analysis. In addition, the scanning and transmission electron microscopies as well as atomic force microscopy were used to study the cross-section and the morphology of the coating. The corrosion behavior of the bare and Ta-coated 316L SS was evaluated by potentiodynamic polarization test. The electrochemical impedance spectroscopy was employed to study the corrosion mechanisms. The results revealed that the structure of Ta coating on either Si and SS substrates is a mixture of α+β phases, while pre-deposition of a thin tantalum nitride seed layer causes to the deposition of pure α-Ta and decrease the sheet resistance from 90 µΩ.cm to 15 µΩ.cm. Microscopic evaluations shows that the Ta coating is compact, homogeneous and defect-free, exhibiting a columnar structure with a surface roughness of less than 6 nm. Furthermore, the corrosion studies show that the Ta coating perform as a physical barrier between corrosive electrolyte and substrate and, in this way, provide a protective efficiency of more than 70%. In this regard, the diffusion of corrosive electrolyte toward the substrates through open porosities was found to be the corrosion mechanism of the Ta coating and the porosity index of the coating was calculated to be about 6%. Manuscript profile -
Open Access Article
21 - Effect of cooling rate on microstructure and corrosion behavior of biodegradable Mg-5Zn-1Y-0.1Ca alloy in simulated body fluid
Hasan Jafari Saeideh NaghdaliAbstract In the present study, the effect of different cooling rate on microstructure and corrosion behavior of Mg-5Zn-1Y-0.1Ca biomedical alloy are investigated. Microstructure observations using optical and scanning electron microscopes showed that the alloy contains MoreAbstract In the present study, the effect of different cooling rate on microstructure and corrosion behavior of Mg-5Zn-1Y-0.1Ca biomedical alloy are investigated. Microstructure observations using optical and scanning electron microscopes showed that the alloy contains α-Mg as the matrix, and Mg3YZn6 and Ca2Mg6Zn3 intermetallic precipitations, having lamellar morphology formed mostly at the grain boundaries. Also microstructure results showed that with increasing cooling rate, the continuity of precipitations increase in grain boundary and inter dendritic zones. The polarization test, as well as the immersion result, confirmed that increasing the cooling rate does not always improve the corrosion properties, and it seems there is an optimal cooling rate resulting in minimum corrosion rate. Abstract: In the present study, the effect of different cooling rate on microstructure and corrosion behavior of Mg-5Zn-1Y-0.1Ca biomedical alloy are investigated. Microstructure observations using optical and scanning electron microscopes showed that the alloy contains α-Mg as the matrix, and Mg3YZn6 and Ca2Mg6Zn3 intermetallic precipitations, having lamellar morphology formed mostly at the grain boundaries. Also mi Manuscript profile -
Open Access Article
22 - Corrosion Inhibition of Polyethylene Glycol on Carbon Steel in Sulfuric Acid Solutions and its Synergism with Schiff Base
sina jahadi mojtaba nasr esfahaniThe inhibiting action of Schiff base and polyethylene glycol (Salpn-PEG) complexes on low-carbon steel corrosion in 0.5 M sulfuric acid was examined using weight loss, potentiodynamic polarization and spectroscopy electrochemical impedance (EIS) techniques. Schiff base MoreThe inhibiting action of Schiff base and polyethylene glycol (Salpn-PEG) complexes on low-carbon steel corrosion in 0.5 M sulfuric acid was examined using weight loss, potentiodynamic polarization and spectroscopy electrochemical impedance (EIS) techniques. Schiff base N, N’-bis(salicyladehyde)-1,3-diaminopropane (Salpn) was synthesized by salicylaldehyde and 1,3- diaminopropane. PEG/Salpn complex with weight ratio 1:4, 2:4 and 3:4 of Salpn and PEG were prepared in methylene chloride solvent by a simple deporotonation procedure. Obtained Results show that PEG/IMZ complex is very effective corrosion inhibitor of carbon steel in the acid environment in compare with PEG, Salpn and noncomplex form of them. Maximum corrosion inhibition was obtained for PEG/Salpn complex with weight ratio 1:4 of Salpn and PEG. The inhibition efficiency increased with the increase in the temperature up to 45°C and decrease in higher temperatures. Results from all the corrosion tests were examined using SEM and are in reasonable good agreement. Adsorption thermodynamic data (〖K 〗_ads and 〖∆G〗_ads ) was calculated using the weight loss data Manuscript profile -
Open Access Article
23 - Theoretical and experimental study of Imidazolium Ionic Liquid Effect on the Corrosion Inhibition of 316-Stainless Steel, Using Electrochemical Test Methods and Quantum Mechanics Theories
Reza Safari ALI EHSANI Hamid EbrahimiIn this study, the impact of )1-Buthyl-3-methyl imidazoloum hexa fluorophosphatesas( a new inhibitor on the corrosion of stainless steel 316L (SS) in HCl solution was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). MoreIn this study, the impact of )1-Buthyl-3-methyl imidazoloum hexa fluorophosphatesas( a new inhibitor on the corrosion of stainless steel 316L (SS) in HCl solution was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Also, the absorption of inhibitor onto the SS surface followed the Langmuir absorption model with the free energy of absorption ΔG0adsof -8.57 kJ mol-1. In addition, using density function theory (DFT) and atoms-in-molecule (AIM) theories, introduced by Richard Bader, which is a generalization of quantum theory to proper nano-size and molecular systems, the electronic organic-structure and local charge/energy transfer in the imidazole molecular system (as a organic-corrosion inhibitor element) are studied. In the same vein, the atomic electronic properties (such as electron density and its Laplacian), and the HOMO–LUMO gap (HLG) of this organic-molecular system are calculated. The results of the investigation show that proposed compound, as a commodious/economical -green inhibitor, has excellent inhibiting properties for SS corrosion in acidic solution. Furthermore, quantum mechanical results show that nitrogen atoms play domain role in intra-molecular charge and energy transfer (and thus electrochemical mechanism) in this inhibitor. Manuscript profile -
Open Access Article
24 - Corrosion evaluation of industrial inorganic base coating on reinforcement by electrochemical impedance spectroscopy
Yadollah Yaghobinejad Abdollah Afshar Abolghasem DolatiIn this study, the effect of several industrial protective coatings such as alkyd base primer, zinc rich primer and polyamide primer coatings in compassion with the surface paints comprising alkyd, polyamide and polyamine were investigated. For evaluating corrosion and MoreIn this study, the effect of several industrial protective coatings such as alkyd base primer, zinc rich primer and polyamide primer coatings in compassion with the surface paints comprising alkyd, polyamide and polyamine were investigated. For evaluating corrosion and durability of concrete properties, strength of mixture, electrochemical impedance spectroscopy (EIS) and pull of test was accomplished. The outcomes significantly demonstrated EIS method performs an excellent response to corrosion analysis of coating upon the rebar. Beside, in harsh media the two parts of isocyanide-acrylic coating with a surface resistance approximately 7.3 GΩ.cm2 shows the best manner. In this study, the effect of several industrial protective coatings such as alkyd base primer, zinc rich primer and polyamide primer coatings in compassion with the surface paints comprising alkyd, polyamide and polyamine were investigated. For evaluating corrosion and durability of concrete properties, strength of mixture, electrochemical impedance spectroscopy (EIS) and pull of test was accomplished. The outcomes significantly demonstrated EIS method performs an excellent response to corrosion analysis of coating upon the rebar. Beside, in harsh media the two parts of isocyanide-acrylic coating with a surface resistance approximately 7.3 GΩ.cm2 shows the best manner Manuscript profile -
Open Access Article
25 - Improvement in fracture toughness and wear resistance of plasma-sprayed chromia coating by addition of YSZ nanoparticles
Seyed Mahdi Hashemi Nader Parvin Zia ValefiIn the present research, wear behavior of Cr2O3-20YSZ (CZ) and Cr2O3 (C) coatings created using atmospheric plasma spray (APS) process was evaluated. For this purpose, Cr2O3 and YSZ nanopowders were produced after milling for 5h in a high-energy ball mill and subsequent MoreIn the present research, wear behavior of Cr2O3-20YSZ (CZ) and Cr2O3 (C) coatings created using atmospheric plasma spray (APS) process was evaluated. For this purpose, Cr2O3 and YSZ nanopowders were produced after milling for 5h in a high-energy ball mill and subsequently plasma spraying of the agglomerated powders was carried out on 304L substrates. Microstructural characterization of these ceramic coatings was performed using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and optical microscope. Mechanical tests including adhesive strength, fracture toughness, and micro-hardness were used so as to explain the coatings wear behavior. Sliding wear test was conducted using a ball-on-disk configuration against an alumina counterpart at room temperature. Addition of YSZ particles to the Cr2O3 matrix due to the phase transformation toughening mechanism associated with tetragonal zirconia resulted in an increase in the fracture toughness while decreased the micro-hardness. It was found that the composite coatings had the friction coefficients of the proper order of 0.11-0.15. The CZ composite coating compared to the C coating showed the higher wear resistance so that the weight loss was obtained as 11 and 31 mg, respectively. Observation of the wear tracks of the coatings indicated that the lower wear rate of the CZ coating was attributed to its higher toughness and therefore filling the pores due to the higher plastic deformation of its wear debris. Manuscript profile -
Open Access Article
26 - Effect of Temperature, Voltage, Time of Anodizing and Applying Nickel-Phosphor Electro less Coating on Hardness and Corrosion Behavior of 2024 Aluminum Alloy
masoud soltani Ali Shafyei Reyhane Alliramezani Saeed AkhavanIn order to improve the surface properties and the greater use of aluminum and its alloys in various industries, especially aerospace, different coating methods have been introduced. Anodizing and electroless plating are the most widely used methods for this purpose. In MoreIn order to improve the surface properties and the greater use of aluminum and its alloys in various industries, especially aerospace, different coating methods have been introduced. Anodizing and electroless plating are the most widely used methods for this purpose. In this research, the effect of temperature and voltage of anodizing on the surface properties of anodic aluminum oxid (AAO), producred on 2024 aluminum, was investigated. The results showed that with increasing voltage and decreasing temperature, the thickness and roughness of coatings increased. An optimal voltage (45 V) was obtained to achieve the highest hardness at all temperatures. The study of the thickness and hardness of the optimum sample also showed an increase in these two parameters with increasing time. FESEM studies also revealed that by carefully controlling on the anodizing conditions, a structure with regular nano-cells could be obtained. The two step anodizing significantly increased the order of the oxide layer cells. SEM, EDS, and XRD results indicated that the possibility of Ni-P electroless coating applying on anodized aluminum in SLOTONIP 70A solution is well established. To investigate and compare the corrosion behavior of AAO and AAO/Ni-P coatings with aluminum substrate, the polarization method and tafel extrapolation was used. The results indicated that the high corrosion resistance of 2024 aluminum alloy was achieved in the presence of Ni-P electroless coating on anodized alloy. The heat treatment of the samples at different temperatures showed that the highest hardness of the final coating (1185 vickers) would be achieved at 400 °C, and the heat treatment time at this temperature after 75 minutes would not have much effect on the hardness. Manuscript profile -
Open Access Article
27 - Corrosion monitoring of sulfuric acid tank under anodic protection by electrochemical noise
احسان صائب نوری Mousa MohammadianIn this research, the tanks made of carbon steel, similar to the practical conditions and in the form of pilot, was investigated. The tank containing 98% and 72% sulfuric acid was evaluated by potentiodynamic polarization test, open circuit potentials and potentiostatic MoreIn this research, the tanks made of carbon steel, similar to the practical conditions and in the form of pilot, was investigated. The tank containing 98% and 72% sulfuric acid was evaluated by potentiodynamic polarization test, open circuit potentials and potentiostatic test. Also, electrochemical noise measurement was carried out before, during and after the anodic protection, and the results were analyzed by statistical analysis at time intervals. . By analyzing the frequency range, PSD curves were obtained and it was observed that the values of slope and current and potential skewness could be used to determine the deviation or non-deviation of the normal distribution of electrochemical noise data. It was also found that by using spectral density curves, it is possible to eliminate the negative effects of additional noise and obtain complete information about the corrosion process. Noise resistance was obtained, but the noise resistance could be applied qualitatively to determine the corrosion rate. In this study, it was concluded that the electrochemical noise method is an efficient method for studying corrosion phenomena, such as crevice corrosion and anodic protection system during protection of tanks and heat exchangers in sulfuric acid. It was found that for a mild steel tank in Sulfuric Acid 98%, during protection, the slope value of the ROLL-OFF region was 2.4 and for dilute sulfuric acid 4.4, and it was found that in this area, the anodic protection was considerably high for carbon steel so protection in the sulfuric acid solution 72% is more suitable. Manuscript profile -
Open Access Article
28 - The Influence of Sensitization Heat-treatment and Surface Finishing on the Properties of the SAF 2205 Duplex SS Passive Layer
Khashayar Morshed-Behbahani Mahmoud Pakshir Pooria Najafisayar Nika ZakerinIn this study, the properties of the passive layer, formed on the surface of SAF 2205 duplex stainless steels in sulphuric acid solution, were investigated. The degree of sensitization of the samples sensitized for 1 h and 5 h were evaluated using double loop electroche MoreIn this study, the properties of the passive layer, formed on the surface of SAF 2205 duplex stainless steels in sulphuric acid solution, were investigated. The degree of sensitization of the samples sensitized for 1 h and 5 h were evaluated using double loop electrochemical potentiokinetic reactivation technique (DLEPR). The results were in good agreement with those of sodium hydroxide etch tests for classification of structures of duplex stainless steels. In addition, the potentiodynamic polarization test was performed to determine the passive potential range of the solution-annealed samples sensitized samples. Cyclic polarization in anodic branch revealed the beneficial effects of having less surface roughness on the protective properties of the passive layer. Mott-Schottky method was used to evaluate the density of point defects at the surface. The results showed that those samples with finer surface roughness, less degree of sensitization and more polarization cycles have less defects (up to 44%) in their passive layers. So, the more degree of sensitization and surface roughness lead to the formation of less intact passive layer due to the formation of sigma phase and less number of microcells at the surface. Manuscript profile -
Open Access Article
29 - Electrochemical study on hot corrosion behavior of aluminide diffusion coating deposited on inconel 713C superalloy
Esmaeil Taheri Mehdi VerdianIn this study, the hot corrosion resistance of diffusion aluminide coating on Inconel 713C was investigated using electrochemical techniques. In this regard, potentiodynamic polarization tests were performed at 750 °C in two kinds of molten salts. The former contain MoreIn this study, the hot corrosion resistance of diffusion aluminide coating on Inconel 713C was investigated using electrochemical techniques. In this regard, potentiodynamic polarization tests were performed at 750 °C in two kinds of molten salts. The former contained 70% sodium sulphate and 30% sodium chloride. The latter was composed of 70% sodium sulphate, 25% sodium chloride and 5% vanadium pentoxide. The phase composition and microstructure of coatings and corrosion products were investigated using XRD and SEM-EDS techniques. The results showed that in the presence of vanadium, the protection efficiency of coatings increased and a current-independent region was observed in anodic polarization curve. Here, a compact corrosion product layer was seen. In absence of vanadium, both coated and uncoated samples exhibited similar corrosion rates. However, in comparison to vanadium-containing environment, all samples showed lower corrosion rate. In this case, the coatings exhibited active anodic behavior. The corrosion products were porous and discontinuous in vanadium free environment. Manuscript profile -
Open Access Article
30 - Investigating the oxidation and electrical behavior of AISI 304 steel coated with cobalt for the application of solid oxide fuel cell
Mohammad Reza Ashorzadeh Morteza Zandrahimi Hadi EbrahimifarOxidation resistance and electrical conductivity of stainless steels used as interconnects in solid oxide fuel cells can be improved by using a conductive and protective coating layer. In this study, AISI 304 austenitic stainless steel was coated in a cobalt powder base MoreOxidation resistance and electrical conductivity of stainless steels used as interconnects in solid oxide fuel cells can be improved by using a conductive and protective coating layer. In this study, AISI 304 austenitic stainless steel was coated in a cobalt powder base pack mixture. Isothermal oxidation test was used to investigate the oxidation resistance of coated and non-coated steel. Area specific resistance (ASR) was also measured as a function of oxidation time at 800 °C. Microstructure of coated and oxidized samples was studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) device. The results showed that cobalt coated samples showed better oxidation resistance than non-coated samples. The results showed that increasing the temperature would increase the area specific resistance. The cobalt coating layer also converted to CoFe2O4, Co3O4 and CoCr2O4 spinels during the isothermal oxidation process. Cobalt spinels exhibited less ASR (27.4 mΩ cm2) compared to the uncoated sample (60.5 mΩ cm2). Manuscript profile -
Open Access Article
31 - The effect of parameters of pulse Electrodeposition and post annealing on properties of Cobalt-tungsten alloy coating
سمیه اباذری سیوندی سعید رستگاری شهرام خیراندیشcobalt-tungsten anano structure alloy coating was produced using pulse electrodeposition in 200 Hz pulse frequency from citrate electrolyte at 60 °C. In this study the influence of cobalt ions concentration in solution and duty cycle on crystal structure, grain size Morecobalt-tungsten anano structure alloy coating was produced using pulse electrodeposition in 200 Hz pulse frequency from citrate electrolyte at 60 °C. In this study the influence of cobalt ions concentration in solution and duty cycle on crystal structure, grain size, hardness and corrosion resistance of coating was investigated. Surface morphology and composition of coatings was examined by scanning electron microscopy (SEM) and (EDS) analysis. The crystallite size of the coatings calculated from the x-ray diffraction patterns using the Scherrer equation. Micro hardness of the coatings was assessed using a Vickers micro-indenter. Results showed that electrodeposited coating at 0.2 mol/l cobalt sulphate and 60% duty cycle with 1A/dm2had optimum coating on 758 Hv. Annealing amorphous coating was produced at current density of 4 A/dm2 in high vacuum pressure makes crystalline coating. Increasing temperature at 600°C makes a well-developed polycrystalline structure of Co3W and CowO4 in the coating. Microhardness of coating increased from 436 Hv to 1059 Hv after heat treatment at 600 °C. Heat treatment of coating improved the corrosion resistance of coating. The coating heat treated at 400 ºC had minimum corrosion rate. Manuscript profile -
Open Access Article
32 - Investigating the effect of temperature and time of fusing process on the microstructure and wear performance of plasma sprayed NiCrBSi coatings
Mohamad Hajiloo Zia ValefiIn this work, self-fluxing NiCrBSi coatings were deposited by plasma spraying. Simultaneous effect of temperature and time of the fusing heat treatment on microstructure, surface roughness and microhardness as well as wear performance of these coatings was evaluated. Fu MoreIn this work, self-fluxing NiCrBSi coatings were deposited by plasma spraying. Simultaneous effect of temperature and time of the fusing heat treatment on microstructure, surface roughness and microhardness as well as wear performance of these coatings was evaluated. Fusing process was carried out at 1000, 1050 and 1100˚C for 5, 15 and 25 min. The morphologies and microstructures of the coatings as well as the wear tracks were characterized using optical microscope and scanning electron microscope. X-Ray Diffraction was applied to determine the phase composition of coatings. Wear performance of the fused coatings was investigated by Pin-On-Disk test. In consequence of the fusing process, the thickness, porosity and surface roughness decreased, the splat boundaries were eliminated, the microhardness increased, a metallurgical bond was created between the coating and the substrate, and hard carbide and boride precipitates (CrB and Cr7C3) were formed. Exceeding the optimum parameters of the fusing caused over-fusing phenomenon and thereby, degradation of coating properties. It was found that the temperature of 1000˚C and the time of 5 min are the optimum conditions of fusing process in this study, as the lowest porosity, the highest microhardness as well as the best wear performance were obtained in coating fused at these parameters. Dominant wear mechanism in this sample was abrasive wear. Manuscript profile -
Open Access Article
33 - The effect of Pt on type II hot corrosion behavior of Si-aluminide coatings with lower silicon than the critical amount
Seyed Amir Azarmehr kourosh shirvani JozdaniIn this paper, the effect of adding a low amount of platinum to slurry Si-modified aluminide coatings containing silicon less than the amount required to provide complete protection in these coatings is investigated. In addition to the coatings characterization, the rol MoreIn this paper, the effect of adding a low amount of platinum to slurry Si-modified aluminide coatings containing silicon less than the amount required to provide complete protection in these coatings is investigated. In addition to the coatings characterization, the role of platinum on the type II hot corrosion behavior of coatings has been discussed. To create silicon and silicon-platinum aluminide coatings, a slurry silicoaluminzing method was applied to samples of Ni-base superalloy GTD-111 specimens, which was previously Pt-electroplated on some of them with a thickness of 2 μm. The amount of silicon in the slurry was 10% by weight relative to total solid of the slurry, so that the amount of silicon in the coating is less than the critical amount required for complete protection. The type II hot corrosion test was carried out using a furnace method with Na2SO4-60mol% V2O5 at 700 °C. After 20 hours of hot corrosion, Al2O3 protective oxide and non-protective oxide NiAl2O4 were detected in silicon-platinum- and silicon-aluminide coatings, respectively. In the absence of platinum, the Ni3V2O8 phase was also found to be a product of NiO and NiAl2O4 dissolution in type-II hot corrosion condition. At the end of the 80-hour hot corrosion, unlike the silicon-aluminide coating, silicon remained in the silicon-platinum-aluminide coating structure. Manuscript profile -
Open Access Article
34 - Studying the Wear Behavior of applied coats on Titanium by Chromium Electroplating and Plasma Nitriding Processes
Arvin Taghizadeh Tabrizi Hossein Aghajnai Hasan Saghafian Farhad Farhang LalehThe surface properties of industrial parts and especially wear behavior of them plays an important role in life service of them. Chromium coat and plasma nitriding are two common ways of applying hard coat on diverse substrates. In this paper, both of these coats applie MoreThe surface properties of industrial parts and especially wear behavior of them plays an important role in life service of them. Chromium coat and plasma nitriding are two common ways of applying hard coat on diverse substrates. In this paper, both of these coats applied on titanium substrate as an advanced engineering materials and the wear behavior of them were compared. For this aim, Pin on disk test was carried out and the weight loss was measured. For determining the wear mechanism of the sample, field emission scanning electron microscopy study was carried out on wear traces. Results show that although the achieved surface micro hardness value of chromium coats is higher than nitride samples, 594 HV at current density of 50 A/dm2 and 60 min versus 528 HV at 600 oC for nitride sample, but they show the weaker wear resistance. Adhesive wear mechanism is determined mechanism at both samples. Also, the lowest coefficient of friction is obtained at sample nitride at 600 oC Manuscript profile -
Open Access Article
35 - Effect of Filler Metal on the Oxidation Resistance of 35Cr-45Ni Alloy Weld Metal
Esmaeel Ahmadizadeh Reza Derakhshandeh Haghighi Amin Rabiezadeh Shiva MansourzadehIn this study the effect of UTP 2535 Nb and UTP 3545 Nb filler metals on the microstructure and oxidation resistance of the weld metal of GTAW welded 35Cr-45Ni alloy have been investigated. According to the results, microstructure of the weld metals includes Cr and Nb C MoreIn this study the effect of UTP 2535 Nb and UTP 3545 Nb filler metals on the microstructure and oxidation resistance of the weld metal of GTAW welded 35Cr-45Ni alloy have been investigated. According to the results, microstructure of the weld metals includes Cr and Nb Carides precipitating along the grain boundaries of austenitic matrix. Weld metal of the sample welded with UTP 3545 Nb filler metal showed denser and more continuous carbides which arises from higher Cr content in this filler metal. According to the XRD analysis of the oxidized weld metals at 1000 ℃ for 96 h, all samples represent an external oxide layer, mostly consist of Cr oxide and an internal oxide layer, mostly composed of Si oxide. Weld metal of the sample welded with UTP 2535 filler metal showed the highest weight gain (4.3 mg/cm2) and oxide thickness (20 μm). For the weld metal of the other sample, these values were 3.6 mg/cm2 and 11 μm, respectively. It can be attributed to the higher Cr and Si in the UTP 3545 Nb filler metal. The first element results in a resistant, continuous, and defect free external oxide on the surface, and the latter one leads to formation of a resistant internal oxide, both strongly effective in improving the oxidation resistance of the weld zone. Manuscript profile -
Open Access Article
36 - Microstructure and Ablation Resistance of ZrC Coating Prepared by Atmospheric Plasma Spraying (APS) and Solid Shielding/ Shrouded Plasma Spraying (SSPS) Methods on SiC-Coated Graphite
Akbar Eshaghi Zia Valefi Naser EhsaniIn this paper ZrC coating was prepared on SiC coated graphite as a substrate by atmospheric plasma spray (APS) and solid shielding/ shrouded plasma spray (SSPS) methods. Microstructure observation and phase identification of the coatings were performed by scanning elect MoreIn this paper ZrC coating was prepared on SiC coated graphite as a substrate by atmospheric plasma spray (APS) and solid shielding/ shrouded plasma spray (SSPS) methods. Microstructure observation and phase identification of the coatings were performed by scanning electron microscopy and X-ray diffraction. The ablation behavior of the coating was evaluated under supersonic flame for 60s. The results showed that the ZrC coating enhance the ablation resistance of SiC coated graphite remarkably. The results of ablation test revealed that the linear and mass ablation rates of the ZrC coating applied by APS method were 3.7×10-3 mm.s-1 and 22×10-3 g.s-1, while those for SSPS coating were 2.2×10-3 mm.s-1 and 14×10-3 g.s-1, respectively. The excellent ablation resistance is attributed to the formation of continuous zirconia (ZrO2) layer on the surface during the oxidation of the ZrC coating. Moreover, the SPS-ZrC coated sample with lowest pores and cracks have better ablation resistance during the ablation test and can protected the graphite substrate against ablation sufficiently. Manuscript profile -
Open Access Article
37 - Influence of Heat Treatment on Microstructure and Mechanical Properties of HVOF Sprayed Cr3C2-NiCr Coating
Pejman Zamani Moghadam Reza Ghasemi Behnaz saeedi Hamid Dahaghin Farhad Shahriari Mahmood MemariDeposition of the Cr3C2-NiCr cermet by the HVOF process results in the dissolution of Cr3C2 in the NiCr metal phase and decreasing the hardness and the elastic modulus of the resulting coating. In this study, Cr3C2-25wt% (Ni-20Cr) powder was applied to Hastelloy X super MoreDeposition of the Cr3C2-NiCr cermet by the HVOF process results in the dissolution of Cr3C2 in the NiCr metal phase and decreasing the hardness and the elastic modulus of the resulting coating. In this study, Cr3C2-25wt% (Ni-20Cr) powder was applied to Hastelloy X super alloy substrates by high velocity oxy-fuel (HVOF) process. Influence of heat treatment on Cr3C2 phase recovery and improvement of hardness and elastic modulus of coatings was investigated. For this purpose, microstructural examination performed by field emission scanning electron microscopy and phase composition analysis by X-ray diffraction (XRD) analysis on the coating before and after heat treatment. Analysis of back scattered electron microscopy images showed that up to 11% of the dissolved carbide phases in the NiCr alloy recovered during heat treatment. In the XRD patterns of the heat-treated coatings, the amorphous regions disappeared and the NiCr peaks pronounced more in the background phase pattern. Also, the hardness and elastic modulus of coating after heat treatment increased by 156 HV0.3 and 98 GPa, respectively. Manuscript profile -
Open Access Article
38 - Influence of pH of Electroplating on Microstructure and Mechanical Properties of Ni-P-Tio2 Composite Coating Fabricated on AISI 430 Steel
Mina Afzali Grouh Morteza Zandrahimi Hadi EbrahimifarOne of the best ways to improve the abrasion resistance and toughness of stainless steels is to apply surface coatings. Among these coatings are nickel base alloy and composite coatings. In this research, nickel-phosphorus-titanium oxide coatings were developed using el MoreOne of the best ways to improve the abrasion resistance and toughness of stainless steels is to apply surface coatings. Among these coatings are nickel base alloy and composite coatings. In this research, nickel-phosphorus-titanium oxide coatings were developed using electrical plating technique and the effect of pH (3, 3.5 and 4) on microstructure and their wear and tear behavior were studied. In this research, nickel phosphorus-titanium oxide coating was deposited onto the AISI 430 steel using electrical plating technique and the effect of TiO2 particles concentration on microstructure and wear behavior was studied. X-ray analysis (XRD) was used to determine the available phases and calculate grain size. Characterization of the coating was performed using SEM (Scanning Electron Microscopy). The michardness was measured by Vickers microhardness device. To test the abrasion resistance of the phosphorus-titanium oxide coated and uncoated samples, a pin on the disk test was used. The results of X-ray analysis showed that the increase of pH causes the increase of grain size. Also the results of microhardness and pin on disk tests showed the increase of pH causes decrease of microhardness and abrasion resistance. The highest hardness (618.18 Vickers) was related to the coating created at pH =3 and TiO2 =40 gr / L. The highest wear resistance and lowest weight loss (0.15 mg) were also observed in the same coating. Manuscript profile -
Open Access Article
39 - Investigating of High Temperature Oxidation and Thermal Shock Properties of YSZ/Al2O3 Composite Thermal Barrier Coatings with Alumina Made by Solution Precursor Thermal Spray
Saeid Taghi-ramezani Zia Valefi Naser EhsaniIn this research, a double layer thermal barrier coating was applied and then an alumina diffusion barrier layer was deposited on the YSZ by two solution precersore plasma and solution precersore flame spraying. High temperature oxidation and thermal shock resistance te MoreIn this research, a double layer thermal barrier coating was applied and then an alumina diffusion barrier layer was deposited on the YSZ by two solution precersore plasma and solution precersore flame spraying. High temperature oxidation and thermal shock resistance tests were done at 1100˚C. Microstructure of coatings were studied by optical Microscopy and Field Emission Scanning Electron Microscopy. Comparison of the microstructures of coatings showed that applying of Alumina with the solution precursor flame spray process upgrades the thermal properties. High temperature oxidation and thermal shock resistance of YSZ/Al2O3 coatings with Alumina applied by the solution precersoure thermal spray with the same compound were studied. Findings showed that applying alumina with the solution precursor flame spray process leads to increase the amount of the deposited splats and proper contact between them, causes to decrease the diffusion of O2 and as a result TGO thickness decreases and also thermal shock resistance increases. Manuscript profile -
Open Access Article
40 - Investigation of the Intergranular Corrosion Behavior of UNS S42000 Martensitic Stainless Steels Using Potentiodynamic Electrochemical Impedance Spectroscopy
Khashayar Morshed-Behbahani Pooria Najafisayar Mahmoud Pakshir Nika ZakerinIn this research, UNS S42000 martensitic stainless steel (SS) samples were subjected to tempering heat treatment at constant temperature of 550 oC for different time duration, ranging between 0.5 and 24 h, so as to assess the intergranular corrosion (IGC) behavior of th MoreIn this research, UNS S42000 martensitic stainless steel (SS) samples were subjected to tempering heat treatment at constant temperature of 550 oC for different time duration, ranging between 0.5 and 24 h, so as to assess the intergranular corrosion (IGC) behavior of the alloy. The microstructural characteristics and electrochemical properties of the alloys were evaluated using scanning electron microscopy (SEM) and anodic polarization method, respectively. The localized attack of the samples was investigated by potentiodynamic electrochemical impedance spectroscopy (PD-EIS) in the transpassive potential region. The results indicated that tempering up to 2 h would be followed by severe intergranular attack at martensite lath interfaces; however, the effect of tempering on corrosion performance of the alloys would be suppressed at prolonged tempering due to desensitization. Moreover, the PD-EIS results revealed that the charge transfer resistance (Rct) values of specimens at 1.10 V can be employed as a primary criterion in order to assess the localized attack of the martensitic SS. In this regard, the lower the Rct value at this DC bias potential, the lower the corrosion resistance to the IGC. These results were in good agreement with the SEM morphologies from the surfaces of corroded samples, indicating uniform corrosion, severe attack and desensitization for samples experiencing no-tempering, short tempering time and prolonged tempering, respectively. Manuscript profile -
Open Access Article
41 - Comparison of microstructure and high-temperature oxidation resistance of NiCrAlY coatings formed by atmospheric plasma spraying (APS) and solid shielding shrouded plasma spraying (SSPS)
Reza Saharkhiz Zia Valefi Masoud Mirjani Saied Taghi-RamezaniIn this research, NiCrAlY powder was applied on steel, and Hastelloy X substrates with solid shielding shrouded plasma spray (SSPS) process and compared with atmospheric plasma spraying (APS). The high-temperature oxidation test was also performed on the coatings, and t MoreIn this research, NiCrAlY powder was applied on steel, and Hastelloy X substrates with solid shielding shrouded plasma spray (SSPS) process and compared with atmospheric plasma spraying (APS). The high-temperature oxidation test was also performed on the coatings, and the microstructure of coatings was studied by optical microscopy (OM) and scanning electron microscopy (SEM). To investigate the influence of the SSPS process on the properties of metallic coatings, variable parameters; such as type of shroud gas (Ar, H2), the gas injection method (internal, external or simultaneous) and the flow rate of that, were examined. During the use of shroud gas, the temperature of the plasma jet has increased significantly. The oxidation test results showed the proper performance of NiCrAlY coating under the protection of argon internal shroud gas with a flow rate of 75SLPM, which was able to perform the best plasma flame protection during spraying. It can lead to a reduction in oxide and porosity of coating up to 8%. Also, the lowest thermally grown oxide (TGO) thickness was obtained for this sample after 200 hours of oxidation, indicating its excellent performance in maintaining the Al for the formation of the continuous α-Al2O3 layer during high-temperature oxidation. Manuscript profile -
Open Access Article
42 - Effect of Protective Behaviour of Biofilm Formed By the Anaerobic Sulfate-Reducing Bacteria on the Corrosion Resistance of the API X42 Microalloyed Steel
mojtaba Baghalzadeh Khalilollah Gheisari Hossien MotamediIn this study, the protective behavior of the biofilm produced on the surface of the API X42 micro-alloyed pipeline steel by the bacterium clostridium sp. as an anaerobic sulfate-reducing bacteria (SRB) is evaluated in a saline simulated soil solution in comparison MoreIn this study, the protective behavior of the biofilm produced on the surface of the API X42 micro-alloyed pipeline steel by the bacterium clostridium sp. as an anaerobic sulfate-reducing bacteria (SRB) is evaluated in a saline simulated soil solution in comparison with the sterile medium. Microstructure and surface morphology was examined by field emission scanning electron microscopy (FESEM) coupled with energy dispersive spectroscopy (EDS). Corrosion properties were investigated using linear polarization and electrochemical impedance spectroscopy (EIS). The results approve the formation of a biofilm consisting of bacterial cells, extracellular polymeric substance (EPS), and corrosion products. In this relatively dense biofilm, semiconductive iron sulfide which is destructive to the corrosion behavior of biofilm is not observed. In addition, the biofilm produced on the metal surface at immersion time of 21 days in the bacterial inoculated medium improves polarization resistance to 7330 Ω.cm2, while at this time the polarization resistance of the protective corrosion products layer created in the sterile condition is about 1421 Ω.cm2. This comparison shows a 5-fold improvement in corrosion resistance as a result of the biofilm's protective behavior. Manuscript profile -
Open Access Article
43 - The Investigation of the Corrosion Resistance of Al/Alumina Composites Fabricated Via ARB Process
Ali Jahangiri Sadri Mohammad Heydari Vini Saeed DaneshmandMetal matrix composites, high mechanical performance, usability at high temperatures, good wear resistance and low creep rate. This type of composite manufacturing method is very important. Among manufacturing processes, ARB process as a method of applying severe plasti MoreMetal matrix composites, high mechanical performance, usability at high temperatures, good wear resistance and low creep rate. This type of composite manufacturing method is very important. Among manufacturing processes, ARB process as a method of applying severe plastic deformation is used on the sheets. In this study 5Wt. % Al/alumina composites fabricated by accumulative roll bonding process up to eight steps using Al1060. Microstructure, mechanical properties and corrosion behavior of the composite were studied by scanning electron microscopy (SEM), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), measurement in 3.5wt% NaCl solution. Corrosion behavior of the composite revealed a considerable improvement in the main electrochemical parameters, as a result of enhancing influence of cold rolling. Also, the electrochemical experiments showed that corrosion resistance of samples increasing with increasing the number of ARB cycles. After 8- cycle ARB have a low corrosion density in comparison with high corrosion density of annealed specimens. Manuscript profile -
Open Access Article
44 - Synthesis of self-healing composite coating due to development of corrosion-resistant of 2024 Al alloy
Amir Hosein Sheikhali Mohammad Amin Kashi sazThe aim of this research is to improve the corrosion resistance and create the active inhibitory in hybrid-silane coatings. Therefor the graphene oxide (GO) nano-sheets and the methylene triphosphonic acid (ATMP) were used as a protective pigment and organic inhibitor c MoreThe aim of this research is to improve the corrosion resistance and create the active inhibitory in hybrid-silane coatings. Therefor the graphene oxide (GO) nano-sheets and the methylene triphosphonic acid (ATMP) were used as a protective pigment and organic inhibitor carrier in the coating, respectively. The peaks appearing in 1059, 1380, 1730, and 3430 cm-1 belong to hydroxyl stretching, carbonyl, hydroxyl bending, and epoxide groups confirmed the successful synthesis of GO nanoparticles by infrared transfer spectroscopy (FTIR). The displacement of two peaks of 230 and 250 nm in GO to 261 and 360 nm in GO-ATMP represent the successful reduction of graphene oxide by ATMP molecules. Then, the corrosion resistance of GO-ATMP coating was evaluated using electrochemical impedance spectroscopy (EIS) and polarization tests. The results showed that the ATMP inhibitor improves the corrosion resistance properties of the coating, and the corrosion current density is reduced as 50%. After successfully inhibiting adsorption on GO plates, the coating (GO-ATMP) was applied on 2024 aluminum alloy sheets. The results of EIS and salt-spray tests showed that the corrosion resistance properties of GO-ATMP coatings improved due to restrict the access of corrosive environment to the metal surface. The intelligent releasing of the inhibitor during electrolyte penetration in scratched area of the coating was confirmed by the formation of a protective film in the scratch area in the electron microscope image of the sample. This caused to restrict the electrochemical reactions. Manuscript profile -
Open Access Article
45 - Investigation of the effect of thermal treatment after welding on the corrosion properties of the interconnecting joint wall of Cu / SS 304 sheets
Ali Ebrahimi Akbarabadi Abbas Saadat Mohammadreza Khanzadeh hamid bakhtiariIn the present study, the effect of thermal treatment on the corrosion behavior and microstructure changes of two-layer stainless-304-Cu sheet steel sheets after the explosive welding process has been investigated. Explosive welding has been done in parallel with an exp MoreIn the present study, the effect of thermal treatment on the corrosion behavior and microstructure changes of two-layer stainless-304-Cu sheet steel sheets after the explosive welding process has been investigated. Explosive welding has been done in parallel with an explosive layer of 46 and 63 µm and a stop distance of 2-3 mm. After explosive welding, the heat treatment process was carried out at 350 and 450 ° C for 8 and 16 hours. Explosive welding with an explosive load and variable stop distance. From the results of the electrochemical impedance test, it can be seen that the n number in the heat treatment sample at 350 ° C and 8 hours is less than the heat treatment sample at 450 ° C and 8 hours, and as a result, the corrosion current in the heat treatment sample The temperature is 350 ° C and the time is 8 hours, which reduces the load transfer resistance. By comparing the heat treatment samples at 350 ° C and 8 hours and the heat treatment at 450 ° C and the time of 8 hours with varying aniline temperature, the annealing time is constant and the heat treatment sample at 450 ° C and time 8 The hour with more annealing temperature has a value of n (0.80), followed by heat treatment at 350 ° C and 8 hours (n = 0.66), due to annealing temperature and reduced energy storage In the chapter. Manuscript profile