Thin bioactive Zn-substituted hydroxyapatite coating deposited on Ti substrate by radiofrequency sputtering

In this study, Zn-substituted hydroxyapatite synthesized by mechanochemical activation was deposited on titanium substrates by a radiofrequency sputtering method. The microstructure, composition, and sputtering rate of the deposited films were examined. The coatings are formed by an amorphous and quasi-amorphous type of structure with good adhesion to the substrate. The elemental composition of the coatings is close to a stoichiometric hydroxyapatite one with a trace of Zn. It was discovered that it is possible to deposit a thin amorphous coating from a crystalline target by increasing the target-to-substrate distance and subsequently decreasing the substrate temperature. This provides a possibility of forming an antibacterial bioactive coating with a high level of bioresorbability which could be used for a rapid antibacterial effect. Also, amorphous calcium phosphate could be used as a component of a multilayer coating comprised of substituted hydroxyapatite in both amorphous and crystalline forms for improved implant stability.