Fabrication of α-Tricalcium Phosphate Porous Body Having a Uniform Pore Size Distribution

An α-tricalcium phosphate (TCP) porous body with a continuous 10-50 μm pore structure was fabricated from slurry composed of β-TCP, potato starch and ultra-pure water through a conventional sintering process. The effect of molding methods on porous structures and mechanical properties of porous body were investigated. Two types of molding methods were applied to the fabrication; i.e. direct casting in an alumina crucible (CP method) and holding with polyurethane sponge (SP method). The CP method resulted in a porous body with high uniformity in pore size distribution of continuous pores around 10-50 μm, while the SP method produced bimodal-type distribution of pores around 10-50 μm and 150 μm. The high uniformity brought about a higher compressive strength of the porous body synthesized by the CP method than that synthesized by the SP method. Porosity of the body could be controlled from 55% to 75% by the content of starch in the slurry. The compressive strength of the porous body synthesized by the CP method increased inversely to its porosity. On the other hand, no significant increase was observed on the compressive strength for the porous body synthesized by the SP method, even when the content of starch in the slurry decreased. This is attributed to macro-cracks in the porous body synthesized by the SP method. Increase in porosity accelerated dissolution of α-TCP body in buffered solution (pH=4). These results indicate that the CP method gives a porous α-TCP body with superior mechanical property as well as controlled porosity.