研削加工された構造用セラミックスの水中強度

概要

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In water strength was measured at room temperature on silicon nitride and silicon carbide having surface microcracks formed by grinding. The strength in water was lower than that in air. The strength in water decreased with immersing time, and the strength of silicon nitride immersed for 240h in water was 85% of that in air. However, the strength retained the original value after drying. The decrease in strength in water was observed on a test piece with surface face flaws to cause fracture. These phenomena can be attributed to the reduction in surface energy of new crack faces by absorption of water, lubricant effect for bite between two crack faces and increase in internal pressure of crack tip voids caused by surface tension. The strength degradation in other liquids was slight as compared with that in water. Hence, other strength lowering mechanisms in water have to be proposed.
社団法人日本セラミックス協会の論文
1994-11-01