Polymeric precursor route for the preparation of calcium phosphate compounds

Abstract

A polymeric combustion synthesis is described for the preparation of calcium phosphate compounds. The polymeric gel containing calcium and phosphate ions were synthesised by concentrating a solution of calcium nitrate and ethyl phosphate. When the above gel was introduced to a furnace kept at 500 °C, a self combustion reaction was observed, leaving behind a calcium phosphate precursor powder. The above powder on heat treatment at 1000 °C resulted in β-TCP, HAP or a mixture of the two phases depending on the Ca P ratio in the gel. Dependence of Ca P ratio on the composition of the calcium phosphate phase was studied by XRD. The morphological features of the precursor as well as the heat treated compounds were studied by SEM. The method offers an easy route for the preparation of β-TCP or HAP in the powder or in the porous form.