Medical nanofilms of titanium oxynitride deposited by reactive magnetron sputtering

E. L. Boytsova, L.A. Leonova

Nanofilms are widely used in recent years in different fields of technologies especially in medicine. The methods of thin film coatings depositing are commonly in demand for the obtaining of new materials, including nanostructure. Films for medical purposes, used for many kinds of implants and vascular stents, should improve qualities of the products: biocompatibility, stability of properties and composition, reducing the impact on the surrounding tissue. The complex Ti-O-N-film is one of the most promising coatings for coronary stents [1]. In this work we study the coating of titanium oxynitride obtained by reactive magnetron sputtering in a facility UVN-200MI [2].The aim of this work is investigation the sputtering conditions influence, particularly, the bias voltage Ub = 0-100 V on changing the chemical properties of the composition and morphology of Ti-O-N-films under prolonged contact with physiological liquid (solution NaCl 0,9%) [3]. The substrates for depositing bilateral coatings were the crystal plate of NaCl (10 × 10 × 1 mm). Plasma gases were oxygen (O2) and nitrogen (N2). Coating deposition parameters: cathode material was Ti, the operating pressure in the chamber 0.1 Pa, the power 1 kW, current 3A, the working gas leakage rate 5 ml/min, the bias voltage from 0 V to -100 V. The ratio of the partial pressure pure gases N2 and O2: p(O2)/p(N2) = 1/1, deposition time 60 minutes. Using of X-ray fluorescence analysis (RFlA, Thermo Electron QUANT'X) it was established that Ti-ON coatings are chemically stable, and negative electric bias (Ub = -100 V) leads to the growth of amorphous phase with respect to the nanocrystalline structure for Ub =0 [4].