Tribochemical structuring and coating of implant metal surfaces with titanium oxide and hydroxyapatite layers

The sandblasting process with corundum is used for cleaning, roughening and activating of metal surfaces in dentistry and orthopaedics. The high local energy transfer at the impact point originates the displacement of particles in the surface. In principle, this method can be used for coating surfaces by sandblasting. In this work, we present a newly developed technique, which allows the coating of metal surfaces with titanium dioxide (TiO2) and hydroxyapatite (HA) using a sandblasting process. The blasting material is a composite ceramic consisting of an alumina core (carrier material) covered with a porous shell of titanium dioxide or hydroxyapatite. The technique is applied to titanium substrates; the surface roughness, morphology and composition of the samples are analysed. The procedure results in an averaged surface roughness of 10–15 μm. Energy dispersive X-ray analysis (EDX) indicates the formation of a thin layer consisting of coating material on the metal surface. Furthermore, the traces of corundum crystals, which are inevitable by using the common technique, i.e. sandblasting with single-component grains, are clearly decreased. X-ray diffraction analysis (XRD) indicates mainly the existence of crystalline rutile and hydroxyapatite/β-tricalcium phosphate (β-TCP) on the surface. Therefore, the presented method would be suitable for simultaneously roughening, coating and optimizing the biocompatibility of metal implant surfaces in dentistry and endoprosthetics.