Role of Magnesium Sulfate Solution Impregnation in Properties Improvement of Alumina Based Castables

摘要

High temperature properties and thermal shock resistance (TSR) of alumina based castables are vital for particular applications, for example, purging plug, well block, etc. This work explored the possibility to improve such properties by suitable salt solution impregnation, for which tabular alumina based castables were adopted and impregnated by saturated magnesium sulfate solution under vacuum. Hot and cold strengths in terms of hot modulus of rupture at 1400℃, cold crushing strength and cold modulus of rupture after firing before and after the impregnation were measured. TSR characterized by residual CMOR ratio after one cycle of HOCC-air quenching of the specimens with and without the impregnation was compared. The phase composition was characterized by XRD and microstructure was investigated by means of FESEM and energy-dispersive spectroscopy (EDS). The impregnation can not only remarkably enhance HMOR, CCS and CMOR, but improve TSR as well, which is attributed to the in-situ formed spinel.