Effects of Zr(OH)Effects of Zr(OH)4 Addition Amount on Microstructure and Resistance Coefficients of Al₂O₃-MgO Castable Matrix Addition Amount on Microstructure and Resistance Coefficients of Al2O3-MgO Castable Matrix

Al2O3-MgO castables were prepared using tabular corundum,white corundum powders,α-Al2O3 micropowders and fused magnesia powders as raw materials,using Al2O3-SiO2 gel powders as binding agent.The castables were cast and then sintered at 1 600 ℃ for 3 hours.The effects of Zr(OH)4 content on the sintering characteristics,microstructure of Al2O3-MgO castable matrix were investigated.The porous media model was adopted to describe both the viscous resistance coefficient and the inertial resistance coefficient.Results show an increase in bulk density and viscous resistance coefficient and an decrease in apparent porosity and average pore size were found in Al2O3-MgO castable matrix added applicable Zr(OH)4.When Zr(OH)4 content was 0.5wt%,the matrix had good sintering characteristics (bulk density of 2.56 g·cm-3 and apparent porosity of 24.5%),small average pore-size (1.71 μm) and homogeneous distribution of pore-size.The average pore size of matrix was more crucial than the apparent porosity for the viscous resistance coefficient of the Al2O3-MgO castables.