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Journal of Advanced Ceramics

Keywords

Al4SiC4, carbothermic reduction, hexagonal plate-like, growth mechanism

Abstract

Highly pure Al4SiC4 powders were prepared by carbothermic reduction at 2173 K using Al2O3, SiO2, and graphite as raw materials. The obtained Al4SiC4 powders owned hexagonal plate-like grains with a diameter of about 200-300 μm and a thickness of about 2-6 μm. Based on the experimental results, the reaction of Al4SiC4 formation and grain evolution mechanisms were determined from thermodynamic and first-principles calculations. The results indicated that the synthesis of Al4SiC4 by the carbothermic reduction consisted of two parts, i.e., solid-solid reactions initially followed by complex gas-solid and gas-gas reactions. The grain growth mechanism of Al4SiC4 featured a two-dimensional nucleation and growth mechanism. The gas phases formed during the sintering process favored the preferential grain growth of (0010) and (11¯0) planes resulting in formation of hexagonal plate-like Al4SiC4 grains.

Publisher

Tsinghua University Press

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