Dense Amorphous Zirconia-Alumina by Low Temperature Consolidation of Spray Pyrolyzed Powders

Gandhi, Ashutosh S and Vikram, Jayaram and Chokshi, Atul H (1999) Dense Amorphous Zirconia-Alumina by Low Temperature Consolidation of Spray Pyrolyzed Powders. [Preprint]

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Abstract

Hot-pressing of metastable amorphous ZrO2-Al2O3 powders was performed at low temperatures (873 and 923 K), under moderately high pressures (500 and 750 MPa), and amorphous pellets with 1 to 8 % porosity were obtained. Crystallization of the amorphous pieces between 1173 and 1673 K produced a range of ultrafine microstructures, the finest of which had 6-8 nm grains of tetragonal (ZrO2-40 mol% Al2O3) solid solution formed at 1173 K. Sub-micron grain sizes of the equilibrium m-ZrO2 and -Al2O3 are stable against coarsening at 1673 K. The new technique was applied to produce a silicon carbide reinforced composite with an amorphous ZrO2-80 mol% Al2O3 matrix; the high matrix sinterability overcame the reinforcement constraint. The results suggest a possible solution to the difficulties in bulk processing of amorphous, nanocrystalline and other novel ceramics.

Item Type:	Preprint
Keywords:	metastable amorphous;nanocrystalline;matrix sinterability;Zirconia-Alumina;Pyrolyzed Powders
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	23 Oct 2007
Last Modified:	19 Sep 2010 04:12
URI:	http://eprints.iisc.ac.in/id/eprint/48

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