XU Tingting, SU Yao, WANG Wei
(Institute of Materials, China Academy of Engineering Physics, Mianyang 621908, Sichuan, China)

Abstract: Two kinds of MgO-based multiphase ceramics with different second phases, MgO-CaO and MgO-Y₂O₃, were prepared by high temperature solid state method at 1680 °C for 2 h. SEM images of the cross sections of the samples show that the addition of Y₂O₃ promotes the sintering of MgO. The hydration rate was calculated by measuring the mass change of the samples after being placed in water for 72 h. It was found that the multiphase ceramics had good hydration resistance when the CaO content was less than 20%. Considering the strength, thermal expansion coefficient and thermal shock resistance at 1200 °C, the factors affecting thermal shock resistance were discussed. Finally, a kind of MgO-CaO-Y₂O₃ ternary multiphase ceramic was determined.
Key words: magnesia; thermal shock resistance; calcia; yttria