فهرست مطالب مهدی اکبرزاده مقدم

In this study Ni-MoS2 composite coatings were deposited onto steel substrates by direct-current magnetron sputtering. The MoS2/Ni ratio in the coatings was controlled by sputtering the composite targets. The coatings were characterized X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and nano-indentation and nano-scratch testes. The tribological behavior of the coatings were investigated using the pin-on-disc test at room temperature. The results showed that the thickness, and the hardness of the coatings were 4-6 µm and 850-1300 HV, respectively. The degree of crystallization of the composite coatings increased with increasing Nickel contents. The incorporation of Nickel to MoS2 coatings resulted in a considerable improvement of coating adhesion and hardness. The optimum doping level for Ni-MoSx coatings to show the best tribological properties,) the lowest friction coefficient and wear rate (was 14 atomic percent. The main wear mechanism of coating were delamination and tribochemical.

Molybdenum disulfide (MoS2) is one of the most widely used solid lubricants applied in different ways on the surfaces under friction. these coatings are very sensitive to water vapor and not suitable for applications in moist environments.. One way to improve the durability of a MoS2 film and also to reduce the deleterious effects of humidity and oxidation on its tribological performance is to co-sputter it with a metal in this study Ti-MoSx composite coatings were deposited onto AISI 1045 steel substrates by direct-current magnetron sputtering. The MoS2/Ni ratio in the coatings was controlled by sputtering the composite targets. The coatings were characterized X-ray diffraction (XRD), scanning electron miTioscopy (SEM), energy dispersive X-ray analysis (EDX), and nano-indentation and nano-sTiatch techniques. The tribological behavior of the coatings were investigated using the pin-on-disc test at room temperature. The results showed that the thickness, and the hardness of the coating were 4-6 µm, 850-1400 HV, respectively. The degree of Tiystallization of the composite coatings inTieased with inTieasing doped contents. The incorporation of Ti to MoSx coatings resulted in a considerable improvement of coating adhesion and hardness. The optimum doping level for Ti-MoSx coatings to show the best tribological properties,) with both the lowest friction coefficient and wear rate (was 5 atomic percent. The main wear mechanism of coating were delamination tribochemical and abrasive miTioTiacking.

Molybdenum disulfide (MoS2) is one of the most solid lubricants applied on surfaces under friction condition in different ways. In this study, MoS2 coatings was applied on 316 stainless steel using thermal diffusion method at various temperatures and times. Coatings properties were investigated using SEM, EDX, XRD and FTIR, Hardness Tester and Roughness tester. The results indicated formation of a uniform layer on the surface that contains MoS2 and MoO3-X phases. Coatings have thickness of 20-50 µm and grain size of 400-1000 nm and hardness of 350- 550 HV. Also in this study, the kinetics of diffusion layer between substrate and coating has been investigated. the kinetics of diffusion layer between substrate and coating has been investigated. It was found that thickness of diffusion layer changes with time at constant temperature follow from parabolic equation.The thickness of diffusion layer changes with time at at constant temperature follow from parabolic equation.

Molybdenum disulfide (MoS2) is one of the most widely used solid lubricants applied in different ways on the surfaces under friction. In this work, AISI 316 austenitic stainless steel was coated with MoS2, using chemical vapor deposition (CVD) at four different temperatures (400, 500, 600 and 700°C). Coatings properties were investigated using SEM, EDX, XRD and FTIR, Hardness Tester and Roughness tester. The results showed that with simultaneous evaporation of sulfur and molybdenum trioxide (MoO3) in the CVD chamber, a uniform coating layer containing MoS2 and MoO2 phases is formed. Increase in the substrate temperature resulted in the rise in the proportion of MoS2 to MoO2 phases as well as the thickness of coating. The thickness, grain size and the hardness of the coating were 17-29 µm, 50-120 nm and 260- 480 HV respectively.

In the current study, (Ti, Cr)N coatings were deposited on the D6 tool steel substrates. Physical and mechanical properties of coatings such as microstructure, thickness, phase composition and hardness were evaluated. The friction and wear behavior of the coatings were investigated using ball-on-disc test under normal loads of 5, 7 and 9 N at sliding distance of 500 m, at room temperature. Phase compositions were studies by X-ray diffraction method. Mechanical properties were determined by nano-indentation technique. Scanning electron microscope and energy dispersive spectroscopy were utilized to investigate the microstructures and wear mechanisms. The results clarified that the wear resistance of (Ti, Cr)N and TiN coatings were better than CrN coating. Wear resistance of the Cr-Ti-N coatings was related to Ti content and increased with increasing Ti content. The dominant wear mechanisms were characterized to be abrasive and tribochemical.