Synthesis of double ammonium’calcium pyrophosphate monohydrate Ca(NH4)2P2O7•H2O as the p recursor of biocompatible phases of calcium phosphate ceramics

Abstract

Double calcium’ammonium pyrophosphate monohydrate Ca(NH4)2P2O7•H2O was synthesized as a result of the interaction of calcium carbonate, an aqueous solution containing pyrophosphoric and lactic acids, and ammonia. The synthesized powder turned black after the thermal treatment in a range of 500—700 °C due to amorphous carbon, which is a product of the destruction of the organic nature components present in the prepared powder. After the thermal treatment at 500 °C, the powder is amorphous to X-rays. The phase composition of the powder after the thermal treatment at 600 °C is presented by β-calcium polyphosphate β-Са(PO3)2, while β-calcium polyphosphate β-Ca(PO3)2 and tromelite Ca4P6О19 are observed after the thermal treatment at 700 °C. The calcium phosphate powder colored due to presence of amorphous carbon can be used as a photocured suspension component that increases the resolution in stereolithographic printing of pre-ceramic semifinished products with a specified geometry of the pore space of calcium phosphate ceramic matrices. The synthesized powder of double calcium’ammonium pyrophosphate monohydrate Ca(NH4)2P2O7•H2O can be applied as a precursor of biocompatible phases for the fabrication of calcium phosphate ceramics used in medicine for the treatment of bone tissue defects.