Effect of CaO Addition on Compressive Deformation of Silicon Nitride Ceramic with Y‐Mg‐Si‐O‐N Glassy System |
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| Authors: | Raayaa Wananuruksawong Yutaka Shinoda Takashi Akatsu Fumihiro Wakai |
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| Affiliation: | Secure Materials Center, Materials and Structures Laboratory, Tokyo Institute of Technology, , Midori, Yokohama, 226‐8503 Japan |
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| Abstract: | Creep behavior of Si3N4 polycrystals containing Y2O3‐MgO‐SiO2 glass phase (with and without Calcium oxide CaO] additive) was studied by compression tests between 1500 and 1700°C. We studied the effect of CaO additive on flow stress, microstructural evolutions, and thermal stability of the intergranular glass phase during deformation. While the addition of CaO did not affect grain size, the flow stress decreased with the amount of CaO. This result suggested that the addition of CaO reduced the viscosity of intergranular glass phase. The addition of CaO further improved the thermal stability of the glass phase by suppressing the evaporation at elevated temperatures. |
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