Fabrication of Al2O3 based ceramic matrix composite by conventional sintering and Sol-Gel process

Abstract

Alumina (Al2O3) matrix composites reinforced with 10%, 20% and 40% of 10µm size aluminum particles were fabricated by two processes, namely cold pressing and sintering process and Sol-Gel process. Al2O3, Al, 5% volume fraction of cobalt was mixed together, compacted and then sintered at 400-500oC for 30 minutes to fabricate the CMC. In the Sol-Gel fabrication route the Al2O3, Al, Co were blended with water and aged for 2-3 days to remove all the moisture and to enable oxidation of Al reinforcement. The mixture was cold pressed and sintered at 400-500oC to produce the CMC. The composition analysis of the CMC carried out by EDAX clearly showed that Al2O3 particles were formed by oxidation of Al reinforced in the matrix, effectively forming Al2O3/Al2O3 particulate reinforced ceramic matrix composite. The nature of the bonding at the interface was characterized using Scanning Electron Microscopy (SEM). The amount of porosity was determined using image analyzer based on ASTM B 276 standard. The average micro hardness of the samples was measured. The optimum volume fraction of aluminum for better interface bonding and reduced porosity was determined using the results obtained.