Preparation Of Iron-based Powder Metallurgy Multi-layer Material And Its Tribological Performance Analysis

The iron base powder metallurgy oil bearing is widely used because of its high strength, high hardness, high temperature resistance, good wear resistance, low price and other advantages. But with the development of modern industry, in some condition which require high performance, powder metallurgy bearings oil will appear hardness, strength is insufficient, easy to damage and other issues. Though the mechanical properties can be improved by increasing the density of the products, but the oil-bearing rate decreases and lubricating effect weakened of the material. In view of this situation, from the point of the pore, this paper design the different layer of iron base powder metallurgy oil bearing material, preparation of dense, surface porous oil layer of iron based powder metallurgy material. Through the mechanical, friction and wear test analysis to research the influences of pore changes on the stratified materials, and the mechanism of the friction reduction and wear resistance.The results show that with the increasing content of ZnSt, surface oil content increase significantly, then the tribological properties of multilayer material become better. But when the porosity is too high, the mechanical properties of the composites decrease significantly, while the pore edge grain shedding phenomenon increase, exacerbated by the wear of materials, so the tribological properties of materials are become better firstly and then become worse; Based on determining the content of ZnSt, change the content of TiH2 in surface trimming can help to improve the mechanical properties and oil-bearing material rate, and the sintering process of TiC hard phase can effectively improve the wear resistance of materials; After determining the optimum formula of surface and substrate, adjust the thickness of the surface layer, with the increase of surface thickness, surface hardness and oil content were increased, and the hardness of the matrix changed little, The performance has a tendency to get worse and worse. When the thickness of the surface layer is 50%, the friction effect is the best, and the wear resistance is remarkable. Through changing the speed and variable load test with the single layer material and the existing material, the composite layer has excellent anti friction and wear resistance under the condition of high speed and high load test.