Wear-resistant engineering ceramics

Engineering ceramics have a high application potential for wear-protection of different working parts used for extraction, processing, conveying, and dust collection equipment in mining and mineral industries, as well as some structural rotating parts. The high alumina (Al2O3 content from 91 to 99.5 wt.%), alumina–zirconia, zirconia, and silicon carbide-based ceramics (ABSC) have been studied. They have high mechanical properties, including hardness that is greater than many processed materials, and they are able to withstand high temperatures (greater than 1300°C) and thermal shocks. These ceramics successfully resist various solid and liquid abrasive and corrosive media transported at high velocities and pressures, and at cavitation; they may replace hard metals widely used for wear- and corrosion-protection. The features of the compositions, microstructure, and physical properties of these ceramics, as well as the wear resistance test results, are discussed. The factors affecting wear resistance of ceramics are emphasized; they may be subdivided by the factors dealing with microstructure and properties of ceramics, and by the factors dealing with application conditions (e.g. type of abrasive media, velocity, impingement angle, and others). Wear mechanisms for dense homogeneous oxide ceramics and for coarse heterogeneous ABSC are discussed.