TiC-Al₂O₃複合材料のエロージョン摩耗特性

抄録

Erosion wear properties of pressureless sintered TiC/Al₂O₃ composites were measured by a collision test between Al₂O₃ or SiC particles accelerated in an air stream. TiC/Al₂O₃ composites with a different TiC fraction up to 30 mass%, which had nearly theoretical density, were used as the target materials. In the case of collision by Al₂O₃ particles, the composites including 20-30 mass% TiC had an excellent wear resistance, which wear rate was 1/20 times that of Al₂O₃ monolithic ceramics. On the other hand, in the case of collision by SiC particles, the wear rate of each composite was almost the same as that of Al₂O₃ monolithic ceramic. In order to analyze the effect of the collision particles on wear rate of each composite target material, the relation between the median crack length and the Vickers indentation load was plotted in logarithmic coordinates for both TiC/Al₂O₃ composite and Al₂O₃ monolithic ceramics. The slope of TiC/Al₂O₃ composite was larger than 2/3, which was the theoretical value estimated by indentation fracture model. Since the mean fracture strength of the SiC particles determined by a diametral compression test under quasi-static loading was 2.3 times that of the Al₂O₃ particles, the mean impact force produced by the SiC particles was much larger than that of the Al₂O₃ particles. It seems that the resistance to crack propagation of TiC/Al₂O₃ composites was reduced by collision of SiC particles.