Synthesis of hydroxyapatite/fluoroapatite solid solution by a sol-gel method

A sol-gel method is developed to synthesize hydroxyapatite (HA)/fluoroapatite (FA) solid solution for providing a basis of preparation of the solid solution film or coating. Calcium nitrate-4 hydrate, phosphoric pentoxide and trifluoroacetic acid (TFA) were used as the precursors. Triethanolamine (TEA) was used as a promoter for incorporating fluorine into Ca phosphates. Mixed ethanol solutions of the Ca and P precursors in Ca/P ratio of 1.67 with different amounts of TFA and TEA were prepared; the mixed solutions were dried on a hot plate to convert them to the as-prepared powders. After the powders were calcined at temperatures up to 900 degreesC, HA/FA solid solutions were obtained. It was found that the fluorine contents in the apatite were dependent on the amounts of TFA and TEA in the mixed solutions. (C) 2001 Elsevier Science B.V. All rights reserved.