STRUCTURAL-ANALYSIS OF CALCIUM-PHOSPHATE COATINGS PRODUCED BY PULSED-LASER DEPOSITION AT DIFFERENT WATER-VAPOR PRESSURES

Calcium phosphate coatings have been produced by pulsed laser depositi on (PLD) at different water-vapour pressures. Rietveld refinement of X -ray diffraction (XRD) data allows us to determine that the structure of these coatings is apatitic with carbonate substitution for phosphat e. The carbonate substitution decreases when the chamber pressure is r aised, a fact that has been corroborated by Fourier transform-infrared (FT-IR) spectroscopy. Carbonate concentrations between 5 and 17 wt% h ave been calculated for the crystalline samples. Amorphous coatings ar e produced at the lowest and highest pressures due to the high carbona te concentration in the first case, and possibly to another type of su bstitution (Mg2+, HPO42-, P2O74-) or the inherent kinetics of the PLD process, in the second case.