Calcium phosphate coatings deposited by aerosol chemical vapour deposition

Thin films of calcium phosphates with different crystallinity and Ca/P ratios have been prepared by the pyrosol method and characterised by XRD, FTIR, EDS and SEM. The microstructure, crystallinity and composition of the deposited films can be controlled by modifying the composition of the precursor solution, reactor atmosphere and substrate temperature. Using this method, pure hydroxyapatite with varying crystallinity and microstructure can be obtained under more oxidising conditions, whereas tricalcium phosphate (alpha or beta) or biphasic hydroxyapatite-tricalcium phosphate mixtures can be obtained under argon atmosphere. The ability to vary the calcium phosphate phases deposited has significant implications for the use of these films in implant devices.