Abstract
The addition of alumina into green is often used to reinforce the porcelain body. Several reinforcement mechanisms, such as the formation of the mullite phase, have been proposed. However, detailed mechanisms have not been clarified. In the present study, detailed studies on the reinforcement mechanism of the alumina addition were carried out. The specimen with 20wt% alumina was strengthened 40% than the ordinary porcelain. However, mullite composition of the porcelain does not seem to be related with its strength but the alumina composition seems to be related. Residual alumina particles were observed even after firing. The reinforcement effect was also observed in the case of addition of zirconia particle, which remained solely in the green without forming any complex phases. These results imply that the reinforcement of the porcelain body with alumina addition is achieved by the suppression of the crack growth with alumina particles.
