Journal of Advanced Materials and Processing: 2 (2)

Open Access Article

1 - The Study of High Temperature Oxidation behavior of Different Microstructures of HVOF Thermally Sprayed Coatings
Behnaz Saeedi Alireza Rouhaghdam

Improvement of thermally sprayed coating properties by microstructure modification has been considered as a significant solution. Therefore, in this research the effect of dissolved oxygen content and post heat treatment on the formation and distribution of secondary ph More

Improvement of thermally sprayed coating properties by microstructure modification has been considered as a significant solution. Therefore, in this research the effect of dissolved oxygen content and post heat treatment on the formation and distribution of secondary phase particles, particularly in nano-scale in the coatings during spraying and after that were studied. Ni-5 wt% Al powders were sprayed by high velocity oxy-fuel (HVOF) technique under two different oxygen/fuel ratio to achieve different melting state for feedstock materials. As-sprayed coatings were exposed to complementary heat treatment including heating at 1100 °C under inert atmosphere, then furnace cooling to room temperature. As-sprayed and heat treated coatings were evaluated for high temperature performance. Isothermal oxidation tests were made at 950 °C for 100 h. The results showed that dependent on spraying condition and optimization of the coating microstructure, Ni-based sprayed coatings with low Al content could be utilized as an efficient bond coat or overlay coating. Manuscript profile

Open Access Article

2 - Characterization of nanostructured SnO2 thin film coated by Ag nanoparticles
Monireh Ganjali Mansoureh Ganjali Amir Hassanjani-Roshan Seyed Mohammad Kazemzadeh

Nanostructured SnO2 thin films were prepared using Electron Beam-Physical Vapor Deposition (EB-PVD) technique. Then Ag nanoparticles synthesized by laser-pulsed ablation were sprayed on the films. In order to form a homogenous coated of SnO2 on the glass surface, it was More

Nanostructured SnO2 thin films were prepared using Electron Beam-Physical Vapor Deposition (EB-PVD) technique. Then Ag nanoparticles synthesized by laser-pulsed ablation were sprayed on the films. In order to form a homogenous coated of SnO2 on the glass surface, it was thermally treated at 500°C for 1 h. At this stage, the combined layer on the substrate was completely dried for 8 h in the air at room temperature right after the Ag colloidal NPs were sprayed on the tin oxide layer. The crystal structure and surface morphology of thin film were studied by X-ray diffraction (XRD), electron diffraction x-ray (EDX), transition electron microscopy (TEM) and scanning electron microscopy (SEM). The average crystallite size of SnO2 nanoparticles estimated by XRD was about 9 nm. On the other hand, the SnO2 NPs with 6 nm size were distributed by the TEM image. The thickness of SnO2 –Ag layer was measured about 2.48 µm. Manuscript profile

Open Access Article

3 - Passivity of AISI 316L stainless steel as a function of nitric concentration
Arash Fattah-alhosseini Mohamad Ali Sonamia Atena Loghmani Fariba Zerafati Shoja

In this study, electrochemical behaviour of passive films formed on AISI 316L stainless steel (AISI 316L) in three acidic solutions concentrations (0.3, 0.6, and 0.9M HNO3) under open circuit potential conditions were evaluated by potentiodynamic polarization, Mott&ndas More

In this study, electrochemical behaviour of passive films formed on AISI 316L stainless steel (AISI 316L) in three acidic solutions concentrations (0.3, 0.6, and 0.9M HNO3) under open circuit potential conditions were evaluated by potentiodynamic polarization, Mott–Schottky analysis and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization results showed that the corrosion potentials of AISI 316L shift towards positive direction with increase in solution concentration. Also, these results reveal that the corrosion rate of AISI 316L is enhanced in solutions with higher nitric content. Mott–Schottky analysis revealed that passive films behave as p-type and n-type semiconductors at potentials below and above the flat band potential, respectively. Also, Mott–Schottky analysis indicated that the donor and acceptor densities increased with solution concentration. EIS data showed that the equivalent circuit Rs((RctQdl)(RfQf)) by two time constants is applicable. Also, EIS results reveal that the charge transfer resistance and passive film resistance decrease with solution concentration. Manuscript profile

Open Access Article

4 - Editorial Board

Manuscript profile

Open Access Article

5 - Increasing the hydrogen storage capacity of single-walled carbon nanotube (SWNT) through facile impregnation by TiO2, ZrO2 and ZnO nanocatalysts
Amir Noroozi Saeed Safa

Various nanocomposites of TiO2, ZnO and ZrO2 decorated single wall Carbon nanotubes (SWNTs) were fabricated by facile and template free continuous ultrasonication/stirring of virgin metal oxide nanopowders and SWNTs in ethanol under UV-light illumination. The TEM microg More

Various nanocomposites of TiO2, ZnO and ZrO2 decorated single wall Carbon nanotubes (SWNTs) were fabricated by facile and template free continuous ultrasonication/stirring of virgin metal oxide nanopowders and SWNTs in ethanol under UV-light illumination. The TEM micrographs showed that nanoparticles (NPs) were uniformly dispersed and bonded on the surface of SWNTs. The results of XRD as well as FTIR spectroscopy revealed coexistence of the precursors in each nanocomposite. The Hydrogen storage capacity of the nanocomposites was evaluated by a purpose-built sievert-type apparatus in kinetic mode measurement. The reversible values of hydrogen storage of the virgin single walled carbon nanotube (SWNT) and also the nanocomposites TiO2, ZrO2 and ZnO decorated SWNTs at room temperature was acquired 0.08, 0.4, 0.31 and 0.25 wt.%, respectively. The elevated absorption ability in nanocomposites is explained by catalytically effect of metal oxides in dissociation and compression of hydrogen into the absorbent sites of carbon nanotube (CNT). Manuscript profile

Open Access Article

6 - The Effect of Friction Stir Processing Speed Ratio on the Microstructure and Mechanical Properties of A 430 Ferritic Stainless Steel
Ali Salemi Golezani S. M Arab Sh. Javadi Firooz Kargar

This study is an attempt to investigate the effect of welding rotational and traverse speed on mechanical and microstructural properties of A 430 stainless steel in order to give an effective processing window to achieve an appropriate microstructure and so mechanical p More

This study is an attempt to investigate the effect of welding rotational and traverse speed on mechanical and microstructural properties of A 430 stainless steel in order to give an effective processing window to achieve an appropriate microstructure and so mechanical properties. There are a wide range industrial uses for ferritic stainless steel. There from they have some problems like grain coarsening and martensitic transformation during conventional fusion welding, solid state welding methods has found a great interest. A heavy duty NC machine is used for FSW. Water cooled brass chamber is used to prevent the tool from severe wear and damage. In order to study the effect of rotational to welding speed ratio ( ) on microstructure, rotational speeds of 600, 800 rpm and welding speeds of 50, 100, 150, 200 mm/min with a spindle tilt angle of 3° are selected. Results showed that ferrite grain size decreased by increasing welding speed at constant rotational speeds which prove dynamic recrystallization occurrence in the nugget zone. Mechanical tests showed that strength and hardness of weld zone in increased compared to base metal. Manuscript profile

Open Access Article

7 - Synthesis of Nanostructured MnNiAPSO-34 Catalyst: Catalytic Properties and Performance
Parisa Sadeghpour Mohammad Haghighi

Silicoaluminophosphate (SAPO-34) molecular sieve doped with transition metals, Mn and Ni, with different molar ratios (Mn/Ni=0.33, 3) were investigated for their activity, selectivity and lifetime in biomethanol to olefins reaction. MnNiAPSO-34 nanostructured catalyst w More

Silicoaluminophosphate (SAPO-34) molecular sieve doped with transition metals, Mn and Ni, with different molar ratios (Mn/Ni=0.33, 3) were investigated for their activity, selectivity and lifetime in biomethanol to olefins reaction. MnNiAPSO-34 nanostructured catalyst was synthesized by hydrothermal method and addition of metals was carried out by isomorphous substitution into the crystalline framework of SAPO-34. The nanostructured catalysts were characterized by XRD, FESEM, PSD, EDX, BET and FTIR techniques. MnNiAPSO-34 nanostructured catalyst synthesized with high concentration of Mn, demonstrated larger crystallite size evidenced by XRD analysis. The FESEM results indicated that the concentration of metal ions could affect the morphology of nanostructured MnNiAPSO-34 catalyst due to different rate of crystal growth. The catalytic performance of samples was studied in biomethanol to olefins reaction at atmospheric pressure and GHSV of 4200 cm3/g.h-1 in a fixed bed reactor. MnNiAPSO-34 with high concentration of Mn illustrated higher selectivity toward light olefins and had longer lifetime for which the selectivity of light olefins for this nanostructured catalyst was 60% after 180 min time on stream. Manuscript profile

Open Access Article

8 - A new approach for fabrication of bulk MMCs using Accumulative Channel-die Compression Bonding (ACCB)
Alireza Babaei Hosein Jafarzadeh V. Zakeri Mehrabad

A new severe plastic deformation (SPD) based technique entitled Accumulative channel-die compression bonding (ACCB) is proposed for the fabrication of high strength multi-layered Al/Cu composites for the first time. In order to primarily demonstrate the capabilities of More

A new severe plastic deformation (SPD) based technique entitled Accumulative channel-die compression bonding (ACCB) is proposed for the fabrication of high strength multi-layered Al/Cu composites for the first time. In order to primarily demonstrate the capabilities of ACCB in the fabrication of metal matrix composites (MMCs), AA 1050 and pure Cu strips were processed. The primary Al/Cu sandwich was prepared and subsequently 50% thickness reduction was applied per cycle. The experimental results reveal that thickness of Al and Cu layers decreased by increasing ACCB cycles to where the Cu layers started to neck and eventually rupture. An Al/Cu bulk composite was successfully processed with homogeneous distribution of fragmented Cu layers in the aluminum matrix after 6 ACCB cycles (correspond to effective plastic strain of 5.6). The microstructure evolution and mechanical properties of the processed specimens were evaluated at different ACCB cycles. The results show that microhardness, strength and elongation of the ACCB processed composites increase with increase in the number of cycles. The capability of ACCB in processing bulk multilayered MMCs was proved. Manuscript profile

XML

List of Articles