Oxidation of Zirconium Diboride with Tungsten Carbide Additions
The oxidation resistance of zirconium diboride (ZrB2) ceramics with tungsten carbide (WC) additions was studied. ZrB2 ceramics, nominally pure and with WC additions of 4, 5, and 6 mol%, were densified by pressureless sintering. During heating, the WC that was added to the ceramic dissolved into the ZrB2 matrix, forming a solid solution. Oxidation behavior was evaluated using isothermal furnace oxidation at 1500°C and 1600°C. The presence of tungsten reduced both the weight gain and oxide scale thickness compared with nominally pure ZrB2. After oxidation at 1600°C for 3 h, the thickness of the ZrO2 outer scale was reduced from 4.7 mm for nominally pure ZrB2 to 0.5 mm for the ceramic containing 6 mol% WC. Analysis showed that WC additions improved the oxidation resistance of ZrB2 by changing the morphology of the zirconia scale formed during oxidation.
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Document Type: Research Article
Affiliations: Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409
Publication date: 01 April 2011