Preparation And Mechanism Research Of Cu-Based Multiphase Self-Lubricating Composite

China has a large manufacturing industry of high speed sewing machine, its friction parts occupy a greater proportion in industrial structure and has great influence on economic growth. With the increase of the environmental protection consciousness of people, developing new oil-free lubricating materials is one of main routes to solve oil pollution problems in high speed sewing machine industry. Therefore, it has important scientific research significance and application value to research a new materials that has high wear-resisting performance and no black abrasive dust, meanwhile, it also has good wide-temperature self-lubricating performance.In this thesis, the tin bronze was selected as the matrix and add BN?CaF2/BaF2 and PTFE as solid lubricant, then matrix was reinforced by adding nano-particles, using powder metallurgy method to prepare shaft sleeve which used in high speed sewing machines. The microstructures, morphologies, mechanical property, friction properties and mechanism were analyzed by XRD, SEM, EDS, OM and friction-wear test. The study shows:With increasing BN content, the capacity of BN which free distribution in the matrix increased, the formation, growth of the sintered necks and the densification process become more difficult, which led to the reduction of density, strength and hardness and the increase of porosity. But with increasing BN content, friction coefficient tended to decrease because of it can form solid lubricant film on wear surface, while wear rate decreased firstly, and then increased. When the composite with 2%BN content, it has higher hardness and strength result in minimal wear rate, perfect frictional wear property.The friction coefficient of the samples without CaF2/BaF2 is between 0.64-0.68 and the abrasion loss is 0.56 mg/m. However, the addition of CaF2/BaF2 greatly improves the high temperature frictional wear property at elevated temperature. When CaF2/BaF2 content reached 4%, the friction coefficient of the composite at 500? is between 0.24-0.27 and the abrasion loss of unit distance is 0.08 mg/m.To improve the low temperature friction and wear properties of materials, using vacuum hot-dip fill PTFE into the pore of composites. The friction coefficient of the composite with PTFE is only 0.13-0.15 at room temperature, and the abrasion loss of unit distance is only 0.072 mg/m, The main wear mechanism is slight fatigue wear and oxidative wear.