CAVITATION EROSION OF STRUCTURAL CERAMICS

Various aluminas, zirconias, silicon carbides, silicon carbide-boron c arbide composites, boron carbide and a sialon were eroded for up to 30 h in distilled water at 18-degrees-C using an ultrasonic vibratory fa cility operating at 20 kHz with a peak-to-peak amplitude of 50 mum, an d the progress of erosion was followed by using weight loss and micros copical techniques. The measured incubation period (weight loss less t han 0.1 mg) varied from 15 min for reaction-bonded silicon carbide to 150 min for 99.9% alumina, and the maximum erosion rate varied from 0. 11 mg/h for sialon to 8.25 mg/h for 97.5% alumina. Overall, sialon had the highest resistance to cavitation erosion. Some results depended c ritically on the surface finish. Microscopical details are presented, and their relationships to the erosion damage are discussed.