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Journal of Ceramics
Volume 2013 (2013), Article ID 214974, 9 pages
http://dx.doi.org/10.1155/2013/214974
Research Article

Mineral-Oxide-Doped Aluminum Titanate Ceramics with Improved Thermomechanical Properties

1Center for Ceramic Processing, International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur, Hyderabad 500005, India
2School of Engineering Sciences and Technology, University of Hyderabad, Hyderabad 500046, India

Received 31 May 2012; Accepted 10 July 2012

Academic Editor: Zhenxing Yue

Copyright © 2013 R. Papitha et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Investigations were carried out, on the effect of addition of kaolinite (2Al2O3·3SiO2·2H2O) and talc (Mg3Si4O10(OH)2) in terms of bulk density, XRD phases, microstructure, as well as thermal and mechanical properties of the aluminium titanate (AT) ceramics. AT ceramics with additives have shown enhanced sinterability at 1550°C, achieving close to 99% of TD (theoretical density) in comparison to 87% TD, exhibited with pure AT samples sintered at 1600°C, and found to be in agreement with the microstructural observations. XRD phase analysis of samples with maximum densities resulted in pure AT phase with a shift in unit cell parameters suggesting the formation of solid solutions. TG-DSC study indicated a clear shift in AT formation temperature with talc addition. Sintered specimens exhibited significant reduction in linear thermal expansion values by 63% (0.42 10−6/C, (30–1000°C)) with talc addition. Thermal hysteresis of talc-doped AT specimens showed a substantial increase in hysteresis area corresponding to enhanced microcrack densities which in turn was responsible to maintain the low expansion values. Microstructural evaluation revealed a sizable decrease in crack lengths and 200% increase in flexural strength with talc addition. Results are encouraging providing a stable formulation with substantially enhanced thermomechanical properties.