Application of dissolution experiments to characterise the structure of pulsed laser-deposited calcium phosphate coatings

A dissolution test was performed with pulsed laser (Nd : YAG, 355 nm)-deposited calcium phosphate coatings composed of hydroxyapatite (HA) and α-tricalcium phosphate (α-TCP) in different proportions, as a result of the use of different deposition rates. During immersion in a Ca2+-free Hankʹs solution, the dissolution kinetics were determined while other structural and compositional properties of the coatings were derived. It was possible to infer that the α-TCP is distributed uniformly and that the coating is of a non-columnar compact grain structure. The mass ratio of the phases for each coating was also determined and was related to the X-ray diffraction intensities. When incomplete, the hydroxylation level of the HA in the coatings is completed after immersion.