Alumina Ceramics

Alumina Ceramics

Alumina ceramics generally refer to ceramic materials with α-alumina as the main crystalline phase. Grades such as 75 porcelain, 85 porcelain, 90 porcelain, 95 porcelain and 99 porcelain are available according to different alumina contents. Ceramic materials dominated by α-alumina crystal phase feature high hardness and mechanical strength, good wear resistance and thermal conductivity, high dielectric strength and insulation resistance, low dielectric loss, and stable electrical properties against variations in temperature and frequency. In addition, they are easy to fabricate with uniform and smooth surfaces, and are widely used as electrical insulating materials. More than ten crystal structures of Al₂O₃ have been discovered so far, among which three are primary. Other crystalline phases almost completely transform into α-Al₂O₃ at temperatures above 1300°C.

Thanks to abundant raw material sources, low cost and excellent wear resistance, alumina ceramics enjoy the widest industrial applications. Studies show that the erosion wear resistance of 95% Al₂O₃ ceramic is more than five times that of high-chromium cast iron (Cr15Mo3). In terms of friction and wear, the alumina content affects the wear resistance of alumina ceramics at lower alumina levels. Wear resistance rises with increasing Al₂O₃ content, and this effect is more pronounced under wet grinding conditions.