Effect of titanium oxide addition on sintering performance of magnesia-rich magnesia-zirconia ceramics

MgO-ZrO2 ceramics were prepared using MgO powder calcined with crystal magnesite as starting material and TiO2 as an additive. Samples were mixed with different mass fractions of ZrO2 powder and sintered at 1600 degrees C for 2 h. Effects of added amounts of ZrO2 and TiO2 on the performance of MgO-ZrO2 ceramics were investigated. Results showed that increase in mass fraction of added ZrO2 or addition of small amount of TiO2 significantly promoted performance of MgO-ZrO2 ceramics. Moreover, the improvement effect of TiO2 was more obvious than that of ZrO2. Addition of TiO2 promoted solid solution reaction of ZrO(2 )and MgO, which was the main reason for improved densification. In addition, TiO2 and CaO form CaTiO3, whereas free SiO2 and MgO form Mg2SiO4. These two compounds filled the pores between MgO and ZrO2 grains and improved densification, compressive strength, and thermal shock resistance.