TANG Hai, YUAN Wenjie, ZHU Qingyou, DENG Chengji, ZHU Hongxi
(The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China)

Abstract: In order to address the effects of Ti-bearing compounds, the influence of TiB₂ addition on the properties of alumina-magnesia refractory castables made from tabular alumina and calcined magnesia was investigated. The phase composition and microstructure of castables with TiB₂ addition after calcining at 1150-1450 ℃ were characterized by X-ray diffraction and scanning electron microscope. The results show that TiB₂ as a mineralizer could accelerate the CA₆ formation. The densification of castables was improved as a consequence of the oxidation of TiB₂, which converted into TiO₂ and B₂O₃ at high temperatures. Meanwhile the apparent porosity and linear change of castables with TiB₂ addition decreased, and their strengths increased. The strength of the alumina-magnesia refractory castabless was obviously improved by adding TiB₂. CMOR of composites with 0.87wt.% TiB₂ sintered at 1450 ℃ for 5 h achieved 50 MPa.

Key words: castables; TiB₂; properties