Fabrication of CaAl12O19–CaTiO3 composites and their potential usage for TiAl alloy smelting

Abstract

CaAl12O19–CaTiO3 (CA6–CT) materials are fabricated using a solid sintering method to investigate the effects of TiO2 content on the phase composition, properties, and microstructure of the materials. With increasing TiO2 content, the preferential replacement of Al3+ by Ti4+ in the CA6 crystal increases the concentration of vacancy defects, thereby promoting ion diffusion and mass transfer, which improves the sintering reaction activity. However, as more TiO2 is added, the CaTiO3 phase formed increases the thermal conductivity and mean expansion coefficient of the material at high temperatures, which degrades its thermal shock stability. The CA6–CT refractory showed good corrosion resistance to the Ti6Al4V melt. Except for a slight penetration of iron element, no obvious corrosion occurred at the reaction interface.