Study Of The Wear Mechanism Of Composite Lubrication Coating Lubrication Of .ni60a/mos <sub> 2 </ Sub>

This article use 45 steel as the substrate material, the spraying powder include NiCrAl,Ni60A,La₂O₃ and MoS₂-coated by Ni. The coating powder with three different contents of the MoS₂-coated by Ni adopt mechanical mixed powder means to uniformity mix alloy powder selected with lubricants, using DH-1080 high energy beam plasma spraying equipment to product the thermal spray anti-friction coating. The research adopts UMT-2 microscopic wear tester (USA) to test the friction and wear characteristics of the coating, and discuss the mechanism of the coating. Using S-3000N scanning electron microscope observes the worn surface morphology of the friction surface, and analyses the friction and wear mechanism.The result shows that during the friction experimental time, the friction coefficient of the self-lubricating composite coating changed with the friction time, which presents dramatically diversification. With the prolongation of friction time, the change of the friction coefficient can be divided into three stages, that is, rapidly decreasing stage; slowly decreasing stage; steady maintaining stage. With increasing the content of MoS₂, the friction coefficient of the coating which changed with the increasing content of the MoS₂ presents firstly decreases then increases and the value reach the minimum value when the quality percent of MoS₂ wrapped with Nickel is 35%. Low-friction property of the Ni60A/MoS₂ composite coating is due to the forming of MoS₂ lubricating film. The decreasing of the friction coefficient of the coating is in proportion to the coverage area of MoS₂ lubricating film.The lubricating mechanism caused by solid lubricant is that it could divert to the grinding surface to form the transfer film, in order to change the friction between surfaces into the friction between solid lubricants. During the friction process, the existing of the tensile stress and the fatigue leads the generation and expansion of the crack, thus the lubricating film flakes off, the whole process could be divided into four phases, the decreasing of the thickness of the film, the existing of the crack, the expanding of the crack and the flaking of the lubricating film. It analyses that the existing of the crack of the Ni60A/MoS₂ self-lubricating materials film is caused by the united effects of the mechanical stress and the thermal stress.