Preparation and Tribological Property of Plasma Sprayed Adaptive Ni-Mo-Al-Ag-BN Composite Coating

摘要

In this paper an adaptive Ni-Mo-Al-Ag-BN composite coating was deposited by plasma spraying. Its tribological property from 20°C-600°C were evaluated by using high temperature tribometer. Scanning electron microscopy and Raman spectroscopy were used to characterize the coating and corresponding wear tracks to determine the lubrication mechanisms. The result shows that the friction coefficient of the Ni-Mo-Al-Ag-BN composite coating from 200°C to 400°C is about 0.4 and declines very slightly at 600°C. The wear rates of the coating is 2.0×10~(-4)mm~3/N*m at 600°C and the downward trend is obvious compared with 400°C. Silver provide lubrication below 400 °C. Ag_2MoO_4 were formed with the temperature raised, and acted as high-temperature lubricants above 400 °C. Ni-Mo-Al-Ag-BN composite coating established a new lubrication mechanism model at 600°C. It can be concluded that the plasma sprayed Ni-Mo-Al-Ag-BN composite coating can keep good tribological property at wide range of temperature.