Friction and wear behavior of spark plasma-sintered cBN-added Al2O3–PSZ-based composites

Al 2 O 3 composites, comprising 10 wt% ZrO 2 stabilized with 0.3 wt% MgO (MSZ/Al 2 O 3 ) and 17.5–25 vol% cubic boron nitride (cBN)-added MSZ/Al 2 O 3 , were fabricated by spark plasma sintering technique, and the wear behavior of these composites was evaluated in terms of friction, wear rates, and wear mechanisms by ball-on-disk contact with dry and rotational sliding at room temperature against two different counterparts. The coefficient of friction (CoF) was smaller when sliding against tungsten carbide counterpart than in comparison with that sliding against sapphire ball for both with or without cBN-added composites. While the wear was characterized by a combination of mild abrasion and adhesion wear in the form of micro-cracking, micro-fragmentation, generation, and spalling of the oxidative tribochemical layer for the MSZ/Al 2 O 3 composites, the experimental results have shown that the dominating wear was generated by a third-body wear for cBN-added composites via extraction of hard cBN grains from the matrix and related to density and hardness of the composites against both counterpart materials.