Effect of B2O3 on Volume Stability and Strength of Corundum-based Castables

Abstract

Calcium aluminate cements (CAC) with 0.21 wt% B2O3 and without B2O3 were used as binders of corundum-based castables. The properties of the castables with and without B2O3 after heat treatment at 110 °C, 1,100 °C and 1,450 °C were investigated, with emphasis on studying the effect of B2O3 in CAC on the volume stability and high temperature strength of the castables. It is found that a very small amount (about 0.01 wt%) of B2O3 introduced by the cement alleviates the expansion of the castables after firing at 1,450 °C and decreases the high-temperature strength of castables as the presence of B2O3 should generate liquid phase.

Keywords

• permanent linear change
• hot modulus of rupture
• boron oxide
• corundum castables
• 81.05.je
• ceramics and refractories