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Journal of the Korean Ceramic Society 1985;22(4): 33. |
| 소결질화규소에 있어서 Strength-Probability-Time Diagram 에 관한 연구 |
| 하정수, 이준근 |
| 한국과학기술원 재료공학부 |
| A Study on the Strength-Probability-Time(SPT) Diagram for Sintered Silicon Nitride |
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| ABSTRACT |
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A composition containing a-$Si_3N_4$ with 5w/0 $Y_2O_3$ and 4w/0 $Al_2O_3$ was hot-pressed at 1, $650^{circ}C$ and 350kg/$cm^2$ for 1.5hrs and specimens of the same composition were pressureless-sintered at 1, 75$0^{circ}C$ for 1.5 and 5hrs. By X-ray diffraction it was found that hot-pressed specimens were consisted of $alpha$-and $beta$-$Si_3N_4$ and sintered specimens were consisted of $beta$-$Si_3N_4$ and $Si_3N-4Y_2O_3$ which was crystallized out from the grainboundary phase. The 5-hr sintered specimens had higher degree of crystallization than the 1.5 hr sintered specimens. Among these three different specimens the 5-hr sintered specimens showed the highest strength by hot MOR test at 1, 00$0^{circ}C$. The SPT diagram for the 5-hr sintered $Si_3N_4$ was constructed by measurements of the stress rate dependence of fracture strength. |
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