Hydroxyapatite coatings prepared by a high power laminar plasma jet

For two hydroxyapatite (HA) powders, containing particles differing in mass by a factor of 20, a set of optimum deposition parameters was defined, leading to the coatings with high crystallinity (80-90%), high adhesion strength (60 and 40 MPa for the coating thicknesses of 120 μm and 350 μm, respectively) and excellent microstructure (coatings were without micro- or macro-cracks, without delaminating on substrate-coating surface contact, and possess low porosity, 1-2%). It was shown that higher plasma power (52 kW) did not necessarily lead to a higher HA decomposition.