Properties of CaP coatings produced by reactive RF-magnetron sputtering in a mixture of nitrogen and noble gases

Abstract

Calcium phosphate coatings are widely used to increase the biocompatibility of metal implants. Nowadays various dopants in the structure of calcium phosphate coatings are actively studied. Nitric oxygen is known as an essential mediator of blood flow. Its presence in the structure of calcium phosphate coating can stimulate angiogenesis and promote osseointegration of the implant. This article is dedicated to the study of morphology and physico-chemical properties of the calcium phosphate coatings formed via reactive RF-$$$magnetron sputtering of hydroxyapatite in the mixture of noble gases (Ne, Ar and Xe) and nitrogen with the same volume concentrations. There is a decrease in grain size and an increase in roughness with the growth of the atomic mass of noble gas in the mixture with nitrogen. The Ca/P ratio also decreases with the increase in the atomic mass of noble gas. Coatings formed in Ne + N2 and Xe + N2 gas mixtures are characterized by higher surface free energy in comparison with the ones formed in Ar + N2. It allows us to suggest that the coatings formed in Ne + N2 and Xe + N2 are more biocompatible than ones formed in Ar + N2, however, additional studies are needed to prove it.