Hydration mechanism of a novel PCCP + DCPA cement system.

A novel partially crystallized calcium phosphate (PCCP) + dicalcium phosphate anhydrous (DCPA) system bone cement was introduced and the mechanism of the hydration was studied by means of solubility product constant (K (sp)), XRD, pH value, and BET. Results showed that DCPA was more soluble than PCCP and HA was the most insoluble compound, and DCPA disappeared fast during hydration of the cement. Therefore, the mechanism of the hydration in the PCCP + DCPA system cement was the dissolution and hydrolysis of DCPA and PCCP. And their by-products H(3)PO(4) and Ca(OH)(2) reacted through a acid-base neutralization reaction, thus the DCPA and PCCP dissolution and hydrolysis process happened until DCPA and/or PCCP was exhausted. As the conserving time prolonged, fine nano-scale pores were formed due to the hydroxyapatite precipitated into the pores, which were occupied by water before.