Studies of Ta, Al, and Carbon Sources on Combustion Synthesis of Alumina–Tantalum Carbide Composites

Abstract

Alumina–tantalum carbide (Al₂O₃–TaC and Al₂O₃–Ta₂C) composites were synthesized by incorporating aluminothermic reduction into a self-propagating combustion process. The test specimens adopted were composed of Ta₂O₅, Al, Al₄C₃, and carbon powders. Experimental evidence showed that the use of Al₄C₃ to provide Al and carbon decreased combustion exothermicity and hindered Ta₂O₅ from being fully reduced. In contrast, for the formation of Al₂O₃–TaC and Al₂O₃–Ta₂C composites, Al₄C₃-free samples with molar ratios of Ta₂O₅:Al:C = 3:10:6 and 3:10:3, respectively, exhibited the highest combustion temperature and reaction rate in the self-propagating high-temperature synthesis process and yielded products with very few minor phases.

Keywords:

• Alumina
• Carbide
• Ceramics
• Combustion
• Composites
• Reduction
• Synthesis
• X-ray