Strength behavior of magnesia-based refractories after thermal cycling

The thermal shock resistance of four commercially available magnesia-based refractory bricks mainly used in furnace linings were investigated. Thermal stability of the bricks was tested using the water-quench method. The experimental damage was characterised by visual inspection and determining some residual physical and mechanical properties. Cracks were observed after thermal cycling resulting in loss of strength and materials degradation. The results show that thermal stability of magnesia-based refractories depends strongly on their chemical composition. The addition of chrome and spinel improved the thermal stability of magnesia bricks with magnesia-spinel (MgAl ₂O₄) having better thermal stability than the magnesia-chrome bricks.