119 炭化ケイ素の超微粒子化によるき裂治癒有効温度範囲の拡大(知的材料・構造システム)

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Self-crack-healing driven by oxidation of silicon carbide is the most valuable function to improve poor reliability of ceramics. However, the ceramics composite having crack-healing ability exhibit only small efficient temperature region for crack-healing during service. Therefore, the present authors tried to decrease the temperature that crack-healing reaction becomes active as well as to increase the limit temperature for bending strength by nano-sizing the contained SiC. The present study adapted the following reaction to fabricate alumina composite containing nano-size silicon carbide particles. 3(3Al_2O_32SiO_2)+8Al+6C=13Al_2O_3+6SiC The formed SiC particles have a particle size from 50nm to 150nm and exist in alumina grain and on alumina grain boundary. As a result, the temperature that self-crack-healing become active can decrease 200℃ by SiC nano-sizing. Furthermore, the crack-healed specimen has no large strength decrease up to 1300℃. Therefore, new alumina/silicon carbide nano-composite was found to exhibit the in-situ self-crack-healing efficient temperature region of 300℃.
2006-11-25