Thermal Shock Resistance of ZrO2-Toughened MgO
| Autor: | Mitsutaka Shimaoka, Yasuro Ikuma, Takashi Okamoto, Wazo Komatsu, Tsukasa Shirotori |
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| Rok vydání: | 1989 |
| Předmět: | |
| Zdroj: | Journal of the Ceramic Society of Japan. 97:812-817 |
| ISSN: | 1882-1022 0914-5400 |
| DOI: | 10.2109/jcersj.97.812 |
| Popis: | The effect of a second phase (ZrO2 particles) on the thermal shock resistance of MgO was investigated. MgO doped with 1mol% LiF and MgO dispersed with 10mol% ZrO2 (t-ZrO2 or c-ZrO2) were fabricated by sintering. Sintered specimens were heated to various temperatures, quenched into water or lubricating oil, and then examined by the 4-point bending test to investigate the severity of the thermal shock. The critical temperature difference ΔTc at which the fracture stress of specimens considerably decreased was higher in MgO dispersed with c-ZrO2 (200K in water and 650K in lubricating oil) or t-ZrO2 (250K and 620K) than that in MgO doped with LiF (115K and 300K). These results have been attributed partially to the increase in fracture stress of MgO due to the existence of dispersed ZrO2. The strength of MgO dispersed with t-ZrO2 did not instantaneously decrease at the temperature difference in excess of ΔTc. This behavior was not observed in other specimens. It was thought to be caused by the microcracks created by m-ZrO2 which was also present in the specimen. The critical temperature difference ΔTc of specimens quenched in lubricating oil was higher than ΔTc quenched in water. It was qualitatively in accordance with the prediction of the calculation of heat transfer coefficient. |
| Databáze: | OpenAIRE |
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