The effect of calcia on the grain growth of yttria was investigated. The results showed that, by adding calcia, yttria was sintered at as low as 1300C and abnormal grain growth was observed above 1500C. At above 1600C, lots of closed pores were formed in the coarse yttria grains and the relative density decreased with increasing temperature and prolonging soaking time. Through theoretical analysis, it was known that oxygen vacancies were formed during the solid solution of Ca2+ into Y3+ and they were atributed to the increasing grain boundary diffusion of yttria.

Effect of Calcia Additive on the Grain Growth of Yttria. W.Dai, X.Wang, D.Zhang, D.Sun, J.Ye, J.Yu: IOP Conference Series: Materials Science and Engineering, 2011, 18[16], 222009