Alumina has high melting point and boiling point, high hardness, insulator at room temperature and conductivity at high temperature. Alumina has been used as refractory for melting glass and steel since the 1920s. Zirconia ceramics are widely used in structural ceramics because of their high toughness, flexural strength, wear resistance, excellent thermal insulation and even their thermal expansion coefficient close to metal. In this paper, the important properties and mechanism of zirconia ceramics and its application in various fields are introduced.
