Study On Sintering Techniques And Performances Of Particle-reinforced Copper Matrix Composite

Studied the copper powder in different pressure semi-finished product to finally affect the sinter property and density and its mechanism. Discovered the copper powder when takes shape the pressure is 870 MPa may to get the biggest sinter density. In sinter process, through changing the craft parameter, such as the temperature, the elevation speed of temperature, the time of heat preservation and the pressure during sintering and so on, analyzing the relations between the sinter density and various crafts parameter, proposed the copper powder with the temperature supposed 750 ℃ - 800 ℃, the pressure in 2.1 MPa, and the time of heat preservation is suitable to take 1 hour.Under the foundation of the copper powder sintering, added new ingredients gradually, such as graphite, SiO₂ and enhancement substrate metal ingredients-tin, iron and so on, studied the influence of these ingredients to friction coefficient and wear rate. In the copper - graphite material, the friction coefficient and the wear rate reduces under the different rubbing speed when the graphite content increases from 2.5% to 30%. When the graphite content is lower than 10%, the influence of rubbing speed is obvious to the material friction coefficient, and also along with rubbing speed enhancement, wear rate rapidly increase. When the graphite content is bigger than 15%, the friction coefficient is stable; the wear rate has not obviously increased along with the rubbing speed enhancement. Under the high-speed friction condition, the lubricant performance of graphite and the friction performance of SiO₂ are all dropping. The friction coefficient of copper - graphite material slowly increases with the rubbing speed increasing; the friction coefficient of copper - SiO₂ but reduces suddenly along with the rubbing speed increases. In the braking material, when the tin and other hard enhancement substrate added, the wear rate is remarkably reduced, and the friction coefficient fluctuates slightly. The graphite and the SiO₂ percentage not suitably surpasses 10%, the granularity not suitably is bigger than 0.2 -0.315mm. The suitably thin the granularity ofgraphite and SiO₂ is helpful to the stable friction coefficient, and reduces the rate of wear. To the homogeneous material, with the elevating of the friction coefficient, the wear rate also can have the varying degree increasing.In addition, in the measurement and the course of wear rate calculation, find there are a lot of wear rate expression ways. In the course of rubbing to the brake, especially when different materials carry on wear-resisting performance and compare, it should adopt "volume /friction energy ", and the formula is testified.