Templated grain growth of textured mullite/zirconia composites

Abstract

Mullite is an attractive material for advanced ceramic applications, but its low fracture toughness prevents it from widespread industrial applications. Therefore, mullite/zirconia composites were prepared from a reactive mixture of alumina and zircon with additives of TiO2 and MgO to increase mechanical properties and densification. <001> aluminum borate templates were used to nucleate, and texture mullite in [001]. Mullite/zirconia formation started at 1350 degreesC and was complete at 1450 degreesC. Dense mullite/zirconia composites with highly textured mullite were produced after sintering at 1450 degreesC. A relatively constant tetragonal ZrO2 content of 11+/-2 wt.% was retained at room temperature after sintering between 1350 and 1550 degreesC. A high quality of texture with an orientation parameter of 0.22 and a very narrow distribution of elongated mullite grains within 8.8degrees around [001] were successfully produced. (C) 2004 Elsevier B.V. All rights reserved.