Abstract
Biomaterial coatings must have high degrees of crystallinity and phase purity, good adhesive and cohesive integrity and adequate porosity to promote bone ingrowth. The most used coating method is atmospheric plasma spraying. However, the main drawback of this technique is the generation of an amorphous phase and other calcium phosphate phases after the spraying process, which are not present in the feedstock and are not desirable. The use of HVOF as a process for obtaining hydroxyapatite coatings on Ti-6Al-4V was used successfully. With optimised HVOF process parameters, coatings with similar bond strength to plasma sprayed HAp coatings, good microstructure and higher crystallinity degree than atmospheric plasma sprayed ones where hydroxyapatite was the only crystalline phase present were obtained. Coating characteristics were analysed with XRD, EDS, SEM, FTIR which indicated that the coatings had a high degree of crystallinity and good bond strength. Moreover, in vitro response were also evaluated and the strength of the coating to the substrate.
