PREPARATION OF CERAMIC-CERAMIC COMPOSITES AND STUDY THE CRACK HEALING BEHAVIOUR OF 'THESE COMPOSITES

Abstract

A1203/SiC ceramic composite were prepared with varying the percentage of SiC in the alumina matrix as 7.5vol% SiC, 12.5vol%SiC and 15vol%SiC and fabricated by using uniaxial press and then sintered at 1500°C for 12 hours. A crack was developed by using Vickers's indenter. To study the crack healing behavior of these .composites, specimens were crack healed at 1100°C, 1200°C, and 1300°C for lhour in the presence of air. The main conclusions were obtain as follows: (a) A1203/SiC ceramic composites has good crack healing ability (b) the maximum crack length which has been healed was 179μm for 15%SiC/ A1203 composite. (c) The best crack healing condition was found to be 1300°C in air for 1 hour. (d) The maximum crack length which has been healed for -7.5% SiC/ A1203 composite and 7.5%SiC/ A1203 composite was found to be 120 μm, 136 pm respectively.