Description:
Al2O3-cBN ceramics with different amounts of hexagonal boron nitride (hBN) solid lubricant were synthesized under high pressure. The correlation between thermodynamic condition, cBN/hBN addition and mechanical properties of Al2O3-cBN-hBN composites were analyzed. Friction and wear tests were carried out. The volume fraction of hBN was determined. It was found that adding a small amount of hBN can increase the relative density of the composites without affecting the hardness. The cBN particle can improve release efficiency of hBN particles, so that the composites containing only 5 vol% hBN shows excellent self-lubricating performance. However, the truss effect of excessive volume fraction of cBN can affect the pressure transfer efficiency and reduce the mechanical properties of composites. The wear mechanism of the composites can be changed by different content of lubricant. The well-sintered Al2O3-cBN-hBN bulks presents an excellent mechanical property. The hardness of the composites is improved at least by 54% compared with the traditional self-lubricating material on the premise of ensuring fracture toughness and lubrication performance