Grain-Boundary Phase Crystallization of Silicon Nitride with Material Loss During Heat Treatment |
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| Authors: | Akihiko Tsuge Hiroshi Inoue Katsutoshi Komeya |
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| Affiliation: | Metals and Ceramics Laboratory, Toshiba Research and Development Center, Toshiba Corporation, Kawasaki 210, Japan;New Material Engineering Laboratory, Material and Component Group, Toshiba Corporation, Yokohama 235, Japan |
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| Abstract: | An analysis was made of the Si3N4· Y2O3 crystallization process from a compacted Si3N4 powder (composition: 5 wt% Y2O3 and 2 wt% Al2O3) during heat treatment in various powder beds. X-ray diffraction was used to measure the degree of cyrstallization, which was correlated with weight loss. Crystallization and weight loss were affected significantly by the SiO2 content in the packing powder. Crystallization correlated strongly with the weight loss. The dominant loss was attributed to SiO volatilization from the Y-Si-Al-O-N liquid. The crystallization mechanism with the loss of material was interpreted using a solubility—supersolubility diagram at constant temperature. |
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| Keywords: | grain boundaries phase crystallization silicon nitride heat treatment |
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