Consolidation and characterization of Cu, Mg substituted hydroxyapatite by cold sintering

Cold sintering method is an effective route to consolidate powders at temperatures below 300?C. In this study, pure and (Cu, Mg) substituted hydroxyapatite were sintered at 250?C. Ultrapure and substituted hydroxyapatite powders were synthesized by wet precipitation method. Sintering pressure of 250 MPa was used to compact the powders while they were heated simultaneously. 10% (H3PO4) solution was used as a transsolvent for the ionic-substituted hydroxyapatite while distillated water was supplied to the pure one. The yield geometries were characterized for density, thermal stability, microstructure, and the biodegradation in Tris-HCl buffer. The findings indicate that the pure hydroxyapatite compacts has a density of 2.876 g/cm3 (86% TD). Owing to the low sintering temperature the resulting hydroxyapatites have not experienced thermal decomposition, besides no additional phases have appeared. Biologically, the sintered sample (Cu0.25Mg0.75Ca9(PO4)6(OH)2) showed larger degradability (0.0001 g/mm2) than to others after one day of immersion.