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1 - Investigation of adding Cr2O3 on mechanical properties and high temperature oxidation behavior of Stellit6 coating prepared by plasma spraying on IN-738
mostafa tahari Mohammad Gavahian Mohammad Jahanbaze Mohammad Najafi
20.1001.1.24233226.1396.11.1.12.4

In this study, the effect of adding chromium oxide on mechanical properties and high temperature oxidation behavior of thermal sprayed stellite 6 coating on IN-738 has been investigated. For this purpose, first the 0, 10, 20 and 30 %wt. Cr2O3 powder added to satellite6 More

In this study, the effect of adding chromium oxide on mechanical properties and high temperature oxidation behavior of thermal sprayed stellite 6 coating on IN-738 has been investigated. For this purpose, first the 0, 10, 20 and 30 %wt. Cr2O3 powder added to satellite6 and plasma sprayed on the IN_738 substrate after mixing by mechanical milling. The optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometer (XRD) and micro-hardness used for micro-structure, porosity and phase analysis investigation. The isothermal oxidation behavior of composite coatings at 650, 750 and 850 ° C for 50 hours were evaluated. Results shows, the stellit6 / %10wt. Cr2O3 coating has the lowest oxidation rate. On the other hand, this coating shows the higher hardness other than non-reinforcement coating. The phase analysis investigation shows that the Cr2O3 oxide layer is forms during oxidation process on the surface of coatings. Its shows the Cr2O3 reinforcement is preferred areas for chromium oxides in thermal grown oxide (TGO) during oxidation Manuscript profile
Open Access Article
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2 - Optimization of HVOF thermal spraying parameters to improve the oxidation resistance of MCrAlY coating using Response
mostafa tahari
20.1001.1.24233226.1396.11.3.7.3

In this research, effects of different coating process parameters on the final properties of thermal spray coatings obtained from HVOF method are investigated. For this aim, five different levels are considered for four effective parameters (Fuel injection rate, oxygen More

In this research, effects of different coating process parameters on the final properties of thermal spray coatings obtained from HVOF method are investigated. For this aim, five different levels are considered for four effective parameters (Fuel injection rate, oxygen injection rate, powder injection rate and spray distance) on HVOF process by response surface method (RSM) and minimum porosity and minimum oxidation layer thickness are considered as the responses. To investigate the microstructure of coatings, Thermal Grown Oxide (TGO) thickness and porosity, a Scanning Electron Microscopy (SEM) and image analysis method are applied. Oxidation test has done at1100ºC for 50 hours on coated samples. Results show that (oxygen injection rate and powder injection rate), (fuel injection rate and powder injection rate), (powder injection rate and spray distance) have a reaction on each other in the TGO thickness value. Also, (oxygen injection rate and powderinjectionrate), (fuel injection rate and powder injection rate) have a little reaction on the porosity against the other parameters which haven’t any effect on it. Investigation of the coated sample with optimized parameters reveals that porosity of the coating is about 0.5% and TGO thickness is about 5.3 micrometer. Manuscript profile

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