Fabrication of α-Tricalcium Phosphate Ceramics through Two-Step Sintering

Abstract

α-tricalcium phosphate (α-TCP), which shows higher solubility than β-TCP, is bioabsorbable and receives special attention for its ability of turning into hydroxyapatite (HAp) in a physiological condition. Problems occasionally occur as α-TCP porous body is too brittle to be handled. Compressive strengths of β-TCP and HAp dense sintered blocks are reported to be comparable to that of human cortical bone. However, α-TCP dense body has rarely been reported. For fabrication of dense sintered body, two-step sintering (TSS) was applied in this study. The TSS generally has firing processes at the lower temperatures, following that at the higher temperatures. TSS is known as one of most effective processing to prevent grain growth comparing with conventional sintering (CS). Dense body of α-TCP was fabricated by both CS and TSS. TSS processing involves heating specimens to T1 temperature, followed by holding at a relatively lower T2 temperature for 12 h. Microstructures of the sintered bodies were characterized and mechanical properties were also evaluated. The specimen prepared by TSS processing with T1 1400 °C, T2 1300 °C showed the lowest porosity (2.7%) and highest compressive strength (714 MPa) among the prepared specimens. TSS processing might be applicable on densification of calcium phosphate powders to fabricate dense body.