알루미나 세라믹스의 반복적 균열치유 특성
Cyclic Crack Healing Effect of Al2O3 Ceramics
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In this study, the crack healing effects of Al2O3 ceramics based on the heat treatment conditions were investigated. The influence of the additive amounts of SiC nanoparticles and the cycling process of indentation-heat treatment on the crack healing effect of Al2O3 ceramics were also examined. Three-point bending tests were carried out and the morphological changes in the fracture surface were observed by using FE-SEM. As a result, heat-treated samples in a vacuum or air atmosphere showed improved bending strengths compared to un-heat treated samples. This means that cracked specimens can be healed by heat treatment in a vacuum or air atmosphere. The crack healing effect of Al2O3 ceramics that were heat treated in an air atmosphere was much higher than that of those heat treated in a vacuum. After heat treatment, the Al2O3 ceramics with 30 wt% SiC nanoparticles showed a higher bending strength than those with 15 wt% SiC. The cyclic indentation and heat treatment did not remarkably affect the crack healing effect. The SEM images showed that the median crack, indenter mark on the surface, and pores in the fracture surface of a specimen almost disappeared after being heat treated in an air atmosphere.
Abstract
In this study, the crack healing effects of Al2O3 ceramics based on the heat treatment conditions were investigated. The influence of the additive amounts of SiC nanoparticles and the cycling process of indentation-heat treatment on the crack healing effect of Al2O3 ceramics were also examined. Three-point bending tests were carried out and the morphological changes in the fracture surface were observed by using FE-SEM. As a result, heat-treated samples in a vacuum or air atmosphere showed improved bending strengths compared to un-heat treated samples. This means that cracked specimens can be healed by heat treatment in a vacuum or air atmosphere. The crack healing effect of Al2O3 ceramics that were heat treated in an air atmosphere was much higher than that of those heat treated in a vacuum. After heat treatment, the Al2O3 ceramics with 30 wt% SiC nanoparticles showed a higher bending strength than those with 15 wt% SiC. The cyclic indentation and heat treatment did not remarkably affect the crack healing effect. The SEM images showed that the median crack, indenter mark on the surface, and pores in the fracture surface of a specimen almost disappeared after being heat treated in an air atmosphere.
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