LI Xiulin ^{1, 2}, YI Danqing ^{1, 2}, LIU Huiqun ^{1, 2}, WANG Bin ^{1, 2}, REN Yan ¹
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, Hunan, China;
2. Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University,
Changsha 410083, Hunan, China)

Abstract: Nine kinds of glazes were obtained by L9(3⁴) orthogonal testing, using kaolin, quartz, limestone, feldspar as raw materials. Their melting characteristics were comprehensively analyzed, and the 8th glaze was determined as the research subject. The microstructure of the glaze was analyzed by field emission scanning electron microscope and the influence of the glaze on the oxidation resistance of MoSi₂ at low temperature was investigated. The results show that, with the firing temperature increasing, glazes were prone to spread over the matrix,resulting in the defects decreasing. When the firing temperature reached 1250 ℃, the defects reduced dramatically. Thus, the optimum firing temperature was determined as 1250 ℃. As the soaking time increased, the defects of the glazes significantly reduced, with the firing temperature remaining at 1250 ℃. In the oxidation tests at 500 ℃ in the air, the weight gain of the unglazed MoSi₂ increased approximately linearly, the weight of the glazed MoSi₂ with the thickness of glaze layer varying from 4.8 μm to 20.8 μm almost unchanged, indicating that the glaze can significantly improve the oxidation resistance of MoSi₂ at low temperature.

Key words: glaze; microstructure; firing process; oxidation resistance