Preliminary Characteristic of Composite Coatings C/Hap Produced Respectively by Rf Pacvd and Sol–Gel Methods

Abstract

The required high mechanical strength and the reliability of implants on one side and a lack of toxic elements in those materials, on the other side, causes restrictions in use of metal alloys for austenitic steel, alloys of cobalt matrix and even titanium alloys. However, elements harmful to human body structure such as chromium, nickel and vanadium could not have been eliminated so far. An attempt to reduce detrimental effects of above elements on the living organism are surface modifications of materials predicted for implants through the deposition of protective layers. The C/HAp composite coating was prerared by deposition of carbon layer directly on surgical steel with RF PACVD method and manufacturing of hydroxyapatite layer by sol-gel method. It was proved that carbon film significantly increases adhesion of the composite C/HAp coating. It is due to the diffusive character of bonding between carbon layer and metallic substrate not only by adhesion as in the case with hydroxyapatite deposited directly on metal base. Adhesion of both synthesized coatings was determined using nanoindentation technique. X-Ray diffraction was used for phase composition evaluation. Atomic Force Microscope revealed topography of raw, carbon and C/HAp surfaces. Elemental composition of carbon and composite layers was investigated by scanning electron microscope equipped with x-ray energy dispersive spectroscopy detector.