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