Sintering of tricalcium phosphate by HIP

Abstract

Tricalcium phosphate (TCP) was HIP'ed in a glass capsule at 800°C-1100° and 100 MPa for 30 min. Soda-lime glass was more suitable than Pyrex glass as a capsule material because of less thermal expansion mismatch from HIP-sintered TCP. Alumina powder was suitable as a barrier layer between glass capsule and sample, but boron nitride powder seemed to be reacted with the sample. The dense and transparent TCP ceramics were obtained by HIPing above 1000°. In the comparison with pressureless sintering, the HIP treatment lowered the densification temperature as much as 200°C and also improved mechanical properties, 120 MPa for bending strength and 0.8 MPa·m1/2 for fracture toughness.