An improvement in sintering property of β-tricalcium phosphate by addition of calcium pyrophosphate

The sintering behavior of calcium pyrophosphate (CPP, Ca2P2O7)-doped β-tricalcium phosphate [TCP, Ca3(PO4)2], prepared by solid state reaction, was investigated in-situ, using dilatometry. Pure β-TCP undergoes phase transition to α-TCP at about 1200°C; hence pure β-TCP ceramics should be sintered below 1200°C. Pure β-TCP sintered body can achieve a relative density of only 86% when sintered at 1150°C. However, the addition of CPP in the range of 0.5–3 wt% delays phase transition of β-TCP and enables sintering of β-TCP at 1200°C without a phase transformation to α-TCP. Due to this effect of CPP added to TCP, CPP-doped β-TCP ceramics with relative density over 95% could be obtained when sintered at 1200°C for 2 h.