J0405-5-5 Effect of self-crack-healing on thermal shock resistance of ceramics

Abstract

A new methodology to improve thermal shock resistance of ceramics which utilizes self-crack-healing was proposed. Ceramics are anticipated to use as high-temperature materials, because they have higher refractoriness compared to metal materials. However ceramics have low thermal conductivity and low fracture toughness, therefore thermal shock and thermal fatigue could be critical fracture pattern. In the present study, it is attempted that the thermal shock resistance is improved by healing surface cracks which are initiation of the crack propagation due to thermal stress. Mullite containing 15 vol. % SiC particles composite which has excellent self-crack-healing ability was used for the present study. From the results, the surface cracks introduced by thermal shock avoided the crack healed zone, the critical temperature difference could be improved by healing the surface cracks, and the surface cracks introduced by thermal shock could be healed. Thus the thermal shock resistance of ceramics could be improved by using self-crack-healing. Furthermore these results imply self-crack-healing has the longer thermal fatigue lifetime ability.