Papers by Author: Fang Bao Ye

Abstract: Alumina–spinel castables were prepared using tabular alumina and coarse spinel as aggregates, calcium aluminate cement, fused alumina fines, spinel fines and ultrafine alumina as matrixes. Effect of microsilica and dispersant on the properties of alumina–spinel castables were investigated in this paper. The results show that with the same content of microsilica addition, the values of permanent linear change and apparent porosity of samples with different additives fired at 1500°C and 1600°C are noticeably increased. The maximum expansion value is 2.01%, 1.47% and 2.59%, respectively, for Sample B (additive: FS 10), Sample E (additive: sodium tripolyphosphate) and Sample F (additive: sodium tripolyphosphate +H₃BO₃). There is a decrease in the final expansion value with the soaking time increases, which is associated to the sintering shrinkage of the castables in this temperature range under a compression load of 0.2 MPa, Expansion behavior of alumina–spinel castables is much different with different additive addition due to abrupt CA6 crystal growth.

Abstract: Nitrides(Si₃N₄/Sialon) bonded alumina castables were fabricated by in situ nitridation reaction. Effects of the formation of nitrides on the physical properties, hot strength and thermal shock resistance were investigated. The results show that the phase composition of castables is alumina, a-Si₃N₄, b-Si₃N₄ and Si₂N₂O after fired at 1400^ºC and 1450^ºC, and is alumina, b-Sialon and O’-Sialon after fired at 1500^ºC. Hot modulus of rupture and thermal shock resistance of specimens are noticeably improved due to the formation of nitrides.