Influence of Carbon on Sintering of the Al-Si-C-N System Composite

Abstract

The composite in Al₄SiC₄-AlN and Al₄SiC₄-AlN-C system were sintered by a spark plasma sintering method. The powders of metal Al, Si and carbon black and AlN as starting materials were mixed. The mixture was calcined at 1300°C and sintered at 1600° to 1800°C by spark plasma sintering. Shrinkage during sintering, density, microstructure and phase of sintered bodies were measured. X-ray diffraction analysis gave Al₅SiC₄N (15R) and AlN (2H) phases in the bodies sintered at 1750°C. Densification did not occur in some composition in 50 to 80% AlN of the system Al₄SiC₄-AlN, but their densification was accelerated by addition of carbon. By the analysis of shrinkage during sintering and SEM observation of microstructure, the grain of Al₅SiC₄N (15R) and AlN (2H) grew, and pore exclusion was obstructed in the system Al₄SiC₄-AlN, though the grain did not grow, and pore exclusion was accelerated in the system Al₄SiC₄-AlN-C.