جستجوی مقالات مرتبط با کلیدواژه "روانکار جامد" در نشریات گروه "مواد و متالورژی"

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.

In this research, Zn-Ni and Zn-Ni/PTFE coatings were electrodeposited from sulfate-based electrolytes. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used to investigate the corrosion properties of the coatings. Hardness and tribological behavior of the coatings were examined by the Vickers microhardness testing machine and the pin-on-disc method, respectively. Chemical composition and morphology of the as-deposited and worn surfaces of the coatings were studied by a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectrometer (EDS). According to the results, the corrosion current density of the Zn-Ni film was about 30% of that of the composite coating. Hardness of the alloy film was partially decreased by the incorporation of Polytetrafluoroethylene (PTFE) particles. However, the wear loss and coefficient of friction of the Zn-Ni/PTFE coating were, respectively, about 43% and 57% of those of the Zn-Ni film. Moreover, wear mechanism was changed from plastic deformation and adhesive wear to slight abrasion by the co-deposition of PTFE particles.