Preparation and Characteristics of ZrO₂/ZrW₂O₈ Composites with Low Thermal Expansion

Abstract:

The ZrO₂/ZrW₂O₈ ceramic matrix composites have been prepared by the two different processes: (1) ZrO₂ and ZrW₂O₈ powders were mixed directly as raw material, then compacted by cold isostatic pressing under 200MPa, and finally, the ceramic matrix composites with low thermal expansion can be prepared by use of heat-pressing sintering or atmospheric sintering at temperature 1215oC. (2) ZrO₂ (with excess mass) and WO₃ powers were mixed as raw material, then compacted by cold isostatic pressing under 200MPa, and finally, the ZrO₂/ZrW₂O₈ ceramic matrix composites can be made by use of heat-pressing sintering or atmospheric sintering at temperature 1215 oC after ZrW₂O₈ were synthesized by in-situ reaction of ZrO₂ and WO₃ powders at the same temperature. The microstructure, density, ZrW₂O₈ decomposition degree and the thermal expansion coefficient were compared among the sintered samples fabricated by the above two different methods, and affected by the different process parameters. The results show that the ceramic matrix composites with low thermal expansion are really composed of ZrO₂, ZrW₂O₈ and WO₃, and their relative densities are all more than 95%. Compared with the composites prepared by in-situ reaction, the densities, ZrW₂O₈ decomposition degree and the thermal expansion coefficient of the composites made by direct mixing are higher, less and smaller, respectively.

• Periodical: Key Engineering Materials (Volume 768)
• Pages: 87-91
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.768.87
• Online since: April 2018
• Authors: Jin Ping Li*, Cheng Yang, Yu Han Li, Song He Meng
• Keywords: Ceramic Matrix Composites, Characteristics, Low Thermal Expansion, Preparation Processes, ZrO₂/ZrW₂O₈

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