Alumina ceramics generally refer to ceramic materials with α-alumina as the main crystal phase. According to the different alumina content, there are 75 porcelain, 85 porcelain, 90 porcelain, 95 porcelain and 99 porcelain and other grades. Ceramic materials with α-alumina as the main crystal phase have high hardness and mechanical strength, good wear resistance, thermal conductivity, high electrical strength and insulation resistance, low dielectric loss, and electrical properties vary with temperature and frequency. It has excellent properties such as stable changes, and is easy to manufacture and has a uniform and flat surface. It is widely used as an electrical insulating material. So far, more than ten crystal structures of Al2O3 have been found, but there are three main ones. At temperatures above 1300 °C, other crystal phases are almost completely transformed into α-Al2O3.

Alumina ceramic materials are widely used in industry due to their wide source, low price and good wear resistance. Studies have shown that the erosion wear resistance of 95% Al2O3 ceramic material is more than 5 times that of high chromium cast iron (Cr15Mo3). For friction and wear, when the alumina content is low, the alumina content has an impact on the wear resistance of alumina ceramics. With the increase of Al2O3 content, the wear resistance increases, and the effect is more significant in wet grinding.