The recently developed Electrostatic Spray Deposition (ESD) technique was used in order to deposit calcium phosphate (CaP) coatings onto various substrates, since this technique enables deposition of inorganic thin films with a variety of morphological and chemical properties. In the present study, the relationship between various deposition parameters and the physicochemical
properties of deposited coatings was investigated in order to be able to deposit CaP
coatings with defined chemical and morphological properties using ESD.
The results showed that the chemical characteristics of the coatings were determined by both the composition of the precursor solutions (solution acidity, absolute and relative precursor concentrations) and apparatus-related parameters, such as the liquid flow rate and the nozzle-tosubstrate distance. By varying these parameters, several crystal phases and phase mixtures were
obtained (carbonate apatite, carbonated hydroxyapatite, a/b-tricalciumphosphate, monetite, b/g-pyrophosphate, metaphosphate, calcite/calcium oxide). Coating morphology was also shown to be strongly dependent on several deposition parameters. A wide range of coating morphologies was obtained, varying from relatively dense to highly porous, reticular coating surface architectures.
Calcium-phosphate coatings by electrostatic spray deposition
