We investigate the chemical composition and mechanical properties of plasma deposited hydroxyapatite on grit blasted Ti-6Al-4V coupons as models of typical prosthetic hip implants. Nanoindentation is used to extract the mechanical properties of the HA coating and to evaluate the behaviour of the material as a function of distance from the interface. A microscratch technique was used to determine parameters of cohesive and adhesive failure of the material critical in determining the functionality of these devices. This delamination method has not been studied in detail before and is usually considered as unsuitable because of the thickness of the HA and the roughness of the substrate. However, through cross section analysis of the scratch test, we can determine the point at which the HA delaminates from the substrate. It was concluded that spallation occurs locally and there is no evidence of gross spallation indicating that the coating is well adhered to the substrate.