The Study Of Preparation, Microstructure And Properties Of Cu-Based Self-Lubricating Composites

In this paper,Cu matrix self-lubricating composites were prepared by powder metallurgy route in argon atmosphere, respectively. The phases,microstructures and mechanical properties of composites were detected by XRD, SEM. After the friction and wear tests under the different conditions, the worn surfaces and the cross sections, compositions and morphologies of worn surfaces were analyzed by micro-analysis method.And the wear behaviors and mechanisms of Cu matrix composites were systematically investigated.First,we prepare Cu-Graphite self-lubricating composites. The results show that Cu-7.5%graphite self-lubricating composites have better lubricating property , but it has lower mechanical strength. Then we prepared Cu-Graphite-MoS₂ self-lubricating composites with 7.5%graphite content. We found that MoS₂ reacts with copper, forming Cu-S-Mo molybdenum and cuprous sulfide, and cuprous sulfide has self-lubricating property because of its lamellar structure. The study found that Cu-7.5%Graphite-7.5%MoS₂ self-lubricating composite has better tribological properties and higher HV, but its bending strength is lower. Cu-Ni solid solution showed good mechanical properties, so first Ni-Cu mixed-powder ball-milled five hours, make Ni soluble in copper lattice; Then, adding graphite and MoS₂, we prepared Cu-Graphite-MoS₂-Ni self-lubricating composite with 7.5%graphite and 7.5% MoS₂. Experimental results show that mechanical strength of Cu-7.5%Graphite-7.5%MoS₂-Ni heightened, meanwhile its wear mass loss in 30 min increased with Ni content increased.With EG content increased, the density, bending strength, and micro hardness of EG-Ni-Cu self-lubricating composite material would be deceased. In different load, the friction coefficient of EG-Ni-Cu self-lubricating composite materials would be smaller as EG increased; with the loading increased, the friction coefficient of EG-Ni-Cu self-lubricating composite has little change. As the ball milling time becomes longer, 10%Ni-5%EG-Cu self-lubricating composite HV greatens and bending strength decreases. As milling time longer, graphitization degree declines and the friction coefficient of 10%Ni-5%EG-Cu self-lubricating composite materials gets bigger. As milling time longer, in the same load, the weight loss becomes smaller. And the weight loss in 30 min of 5%EG-10%Ni-Cu self-lubricating composite material is as bigger as the load increases.