Application of carbonated apatite coating on a Ti substrate by aqueous spray method

The fabrication and characterization of a carbonate-containing apatite film deposited on a Ti plate via an aqueous spray method is described. The mist of the spray solution emitted from a perpendicularly oriented airbrush was made to strike a warmed Ti substrate. The thicknesses of the sprayed film and those heat-treated at 400 degrees C-700 degrees C under Ar gas flow were in the range 1.21-1.40 mu m. The results of elemental analyses and Fourier transform infrared spectroscopy of the powders that were mechanically collected from the surface of the sprayed film suggest that the film was Ca-10(PO4)6(CO3) center dot 2CO(2) center dot 3H(2)O. The presence of the carbonate ion and the lattice CO2 molecule was confirmed via the aforementioned analyses; the finding was also consistent with the X-ray diffraction patterns of the films and the chemical identity of the sprayed and heat-treated films that were measured using X-ray photoelectron spectroscopy. The sprayed film comprises a characteristic network structure, which contains round particles within the networks, as was observed by field-emission scanning electron microscopy. A scratch test indicated that the shear stress of the sprayed film (21 MPa) significantly improved to 40 and >133 MPa after heat-treatment at 600 degrees C and 700 degrees C, respectively, under Ar gas flow for 10 min. (C) 2012 Elsevier B.V. All rights reserved.