Role of Ceria in Enhancing the Resistance of Aluminosilicate Refractories to Attack by Molten Aluminum Alloy

Rare‐earth doping of aluminosilicate refractory compositions has been shown to impart improved resistance to attack by molten aluminum alloys. The basis for this improved alloy attack resistance was investigated. The addition of rare‐earth oxide to bauxite was found to alter the microstructure to form large, uniformly shaped corundum crystals interlinked with cerium‐containing strands. It was concluded that this unique microstructure was responsible for the enhanced attack resistance of the refractories. Other possible causes for improved alloy attack resistance, such as enhanced sintering, excess oxygen provided by the CeO 2 dopant, or higher thermodynamic stability of the phases formed in the doped refractory compositions, were not consistent with the experimental findings.