Wear and friction behavior of self-lubricating alumina–zirconia–fluoride composites fabricated by the PECS technique

This study examined the wear and friction behavior of pulse electric current sintered Al2O3–ZrO2 composites containing such fluorides as CaF2 and BaF2. The dry sliding wear and friction properties against a commercial alumina bearing ball were investigated using a reciprocal ball-on-plate tribometer. The coefficient of friction of the fluoride-containing Al2O3–ZrO2 composites decreased by approximately 10–20% compared with that of the matrix composite. The wear rate of the fluoride-containing Al2O3–ZrO2 composites was determined to be lower than that of the matrix composite. The following wear rates were observed herein: 0.53×10−6 mm3/m N (CaF2 and low weight fraction of BaF2), 11.41–45.05×10−6 mm3/m N (high weight fraction of BaF2), and 168.17×10−6 mm3/m N (matrix composite). Furthermore, different friction coefficients were observed for the reciprocal sliding test compared with the scratch test due to a difference in the fracture behavior. Because the scratch test employed unidirectional motion, it did not involve fracture behavior due to fatigue or repeated contact.