空気, 水, トルエン中でのダブルトーション法によるハイドロキシアパタイトのクラック進展の評価

概要

論文の詳細を見る
The double-torsion method was employed to study the effect of environments on crack-growth law of hydroxyapatite. Three regions (regions 1, 2 and 3) were distinctly observed for measurement in air. In water only region 1 was observed. As the temperature increased, the crack-propagation curves in water shifted to lower applied K_I values. The change of crack velocity with increasing K_I in region 2 was small compared with those detected in regions 1 and 3. It was argued that crack propagation in region 2 is controlled by the rate of water diffusion towards the crack tip. Region 3 was observed in air and toluene. Intergranular fracture was dominant in the specimen fractured in water, while both transgranular and intergranular fracture were observed in air. On the other hand, the specimens showed only transgranular fracture in toluene. Since a low Ca/P ratio phase was observed at grain boundaries of hydroxyapatite, it was deduced that this phase is selectively dissolved into water.
1995-06-01