Effect of Divalent Elements on the Grain Growth of TZP

摘要

The effect of divalent elements, Mg, Ca, Sr, and Ba, was investigated on the grain growth suppression during sintering to 12Ce-TZP and 3Y-TZP. All of the dopants were effective in reducing the grain size, but the degree of the effectiveness differs for Ce-TZP and Y-TZP. In case of Ce-TZP, Ca was most effective and reduced the grain size to less than 1/3 of the undoped specimen. However, a small amount of the cubic phase appeared in the specimen of 2mol%Ca. On the basis of empirical equation suggested in the literature, the solubility limits of the dopants were estimated. MgO and CaO are soluble but SrO and BaO are hardly soluble. Within the solubility limits, the smallest grain size was obtained by Ca doped specimen. The resulting relationship between the ionic size of the dopant and the grain size was consistent with Hwang and Chen's result. In case of Y-TZP, Sr was most effective and the grain size was reduced to 3/4 of the undoped Y-TZP. The amount of the cubic phase increased with Mg and Ca dopants. The resulting relationship between the ionic size of the dopant and the grain size was consistent with Hwang and Chen's result.