Structure Evolution and Reaction Mechanism of Al₄SiC₄ Ceramics in High-temperature Reduction Atmosphere

Al₄SiC₄ is a promising additive for carbon-containing refractories to improve their oxidation resistance. Al₄SiC₄ ceramics were synthesized from Al, Si, and C powders, which were then placed in the temperature range of 1000-1500 ℃ to simulate the real environment for carbon-containing refractory materials. It is experimentally showed that Al₄SiC₄ initially reacted with CO to form Al₂O₃, SiC, C and aluminosilicate glass in a reduction atmosphere in the temperature range 1000-1400 ℃. When the heating temperature was raised to 1500 ℃, Al₂O₃ and SiC began to react with CO to form Al₆Si₂O₁₃(mullite). The two reaction processes led to the formation of protective films on surface of the carbon-containing refractories, thus inhibiting the oxidation process.