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Effects Of Excess Al2O3 And TiO2 On Microstructure And Properties Of Al2TiO2 Ceramics Prepared from CVD Powders

Published online by Cambridge University Press:  28 February 2011

Saburo Hori
Affiliation:
Kureha Chemical Industry Co., Ltd., 16 Ochiai, Nishikimachi, Iwaki-Shi, Fukushima 974, Japan
Masahiro Yoshimura
Affiliation:
Research Laboratory of Engineering Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-Ku, Yokohama 227, Japan
Shigeyuki Sōmiya
Affiliation:
Research Laboratory of Engineering Materials, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-Ku, Yokohama 227, Japan
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Abstract

The effects of excess AI2O3 and TiO2 on microstructure, bending strength and thermal expansion of Al2TiO5 ceramics were studied by sintering various compositions of CVD Al2O3-TiO2 powders at 1310°C for 4 h. Excess Al2O3 resulted in much higher bending strength with slightly higher thermal expansion, while excess Ti02 resulted in slightly higher strength with lower thermal expansion. The excess AI2O3 and TiO2 were uniformly dispersed as particles on the Al2TiO5 grain boundaries, creating interlocked grains and dispersed microcracks. Excess TiO2 enhanced the material diffusion while AI2O3 did not, and appeared to develop more anisotropy of Al2TiO5 grains, resulting in lower expansion. It was proved that the overall properties of Al2TiO5 ceramics could be improved by dispersing excess Al2O3 or TiO2 uniformly onto the grain boundaries.

Type
Research Article
Copyright
Copyright © Materials Research Society 1986

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