Applied Surface Science, Vol.264, 516-521, 2013
Tribological characteristics of electroless Ni-P-MoS2 composite coatings at elevated temperatures
Ni-P-MoS2 composite coatings were deposited on AISI-1045 steel plate by electroless plating followed by a heat treatment at 300 degrees C for 2 h. The high-temperature tribological characteristics of the composite coatings were evaluated under dry sliding conditions in a tribometer with ball-on-disk configuration. The effect of the co-deposition of MoS2 on the friction and wear behaviors of composite coatings at elevated temperature was investigated. Scanning electron microscopy was used to determine the morphology of the worn surface of composite coating. The chemical states of some typical elements on the worn surfaces were determined by X-ray photoelectron spectroscope. The results indicate that friction coefficient of the composite coatings decreases with the increase of test temperature up to 500 degrees C, and the best tribological properties of Ni-P-MoS2 composite coatings are achieved at 400 degrees C. The worn surface of Ni-P-MoS2 composite coatings are characterized by mild scuffing and deformation. The improvement of tribological properties of the composite coatings was attributed to the formation of the lubricious oxide film composed of oxides of Ni and Mo at high temperatures. With the test temperature increasing to 600 degrees C, the tribological properties of the composite coating begin to deteriorate due to softening of the coating. (C) 2012 Elsevier B. V. All rights reserved.
Keywords:Electroless;Ni-P-MoS2 composite coating;Tribological characteristic;Lubricious oxide film;High-temperature