Preparation and electrical wear characteristics of copper matrix composites reinforced with mixing sized TiB₂ particles

Copper matrix composites reinforced with single sized TiB₂ particles and mixing sized TiB₂ particles were prepared by powder metallurgy, respectively. Effects of mixing sized TiB₂ particles (2 μm+50 μm) on the friction behavior under non-current and current of the TiB₂/Cu composites were studied. Microstructure observation shows that the different TiB₂ particles are evenly distributed in the copper matrix. The higher relative density, the hardness and electrical conductivity of mixing sized TiB₂/Cu composite are obviously better than those of TiB₂/Cu composites reinforced with single sized TiB₂ particles. The results of friction and wear tests show that:The friction and wear properties of mixing sized TiB₂/Cu composites are significantly higher than those of single sized TiB₂/Cu composites. When the mixed ratio of 2 μm and 50 μm TiB₂ particles is 1:2, the TiB₂/Cu composite has the best wear resistance, when the current is 0 A, compared to the composites with 2 μm single sized, its friction coefficient and wear rate decrease by 17.3% and 62.5%, respectively, when the current is 25 A, compared to TiB₂/Cu composites with 2 μm single sized, its friction coefficient and wear rate decrease by 6% and 45.8%, respectively. Meanwhile, its wear surface is more flat and the stability of the current carrying and efficiency of the current carrying capacity are obviously improved. The analysis of wear mechanism shows that:The mixed TiB₂ particles are favorable for improving the current carrying quality of TiB₂/Cu composites. The mixed TiB₂ particles play a supporting role in the friction process, and the small TiB₂ particles disperse and strengthen the Cu matrix. The synergistic effect of that makes the TiB₂/Cu composites have better current-carrying friction and wear resistance.