放電プラズマ焼結により作製したAl₂O₃/Ti界面の焼結過程と機械的特性の評価

抄録

Much attention has been paid to composites made from biocompatible ceramics and metals in the medical field because the composites are expected to exhibit high biocompatibility and mechanical performance. The mechanical properties of interface between ceramic phase and metal phase should be elucidated to evaluate the mechanical properties of the composites. In this study, we fabricated square pillar-shaped specimens with an Al₂O₃/Ti interface by a spark plasma sintering (SPS) technique under various sintering conditions to investigate the sintering process of the Al₂O₃/Ti interface. Firstly, their microstructure was observed with an optical microscope and element diffusion near the interface was measured with an electron probe microanalyzer (EPMA). Then, the Vickers hardness tests and bending tests were carried out to evaluate their mechanical properties. As the results of EPMA measurement, Al atoms were diffused into the Ti phase, while Ti atoms were not diffused into the Al₂O₃ phase. The thickness of reaction layer created at the interface in Ti phase increased with increasing sintering time. As the results of hardness tests, the Vickers hardness was constant in the Al₂O₃ phase, while that in the reaction layer in the Ti phase was low, compared with that in the Ti phase. As the results of bending tests, brittle fracture occurred at the Al₂O₃/Ti interface, and the bending strength was lower than that of monolithic Al₂O₃ and their composites.