Effects of water on cold‐sintered highly dense dicalcium phosphate anhydrous bioceramic using its hydrate

Abstract

AbstractThe dicalcium phosphate anhydrous (DCPA, CaHPO4) bioceramic has long been difficult to prepare by conventional sintering techniques due to its weak thermal stability. Here, the DCPA ceramic is prepared at 250°C by cold sintering process (CSP) using the dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O) as the starting powder. It is found that the dehydration temperature of DCPD powder is greatly reduced during CSP, which facilitates the densification even without additive water. However, the ceramic only reaches a relatively low density of around 90% without additive water, which can be ascribed to the lack of particle rearrangement and the readily loss of dehydration water during sintering. In comparison, a high relative density of 95% can be obtained when the DCPD hydrate is densified with additive water, in which both hydration water and additive water play important roles. The obtained DCPA ceramic with high density exhibits a flexural strength of 46.17 MPa and Young's modulus closer to human bones compared with hydroxyapatite. Combined with the low cytotoxicity, the DCPA bioceramic has great potential to be applied for bone tissue engineering.