CHARACTERISATION AND BIOCOMPATIBILITY STUDY OF A THIN TITANIUM FILM OBTAINED BY PVD ON AISI 316L STAINLESS STEEL

摘要

The metallurgical, mechanical and electrochemical characteristics of a thin film of titanium deposited on AISI 316L by PVD (Physical Vapour Deposition) were investigated using various experimental techniques. The results were compared with those obtained for the substrate characterised in the same conditions, with commercially pure titanium used as the control. In order to obtain a clear idea about one of the most important properties of an implant, namely its biocompatibility, and to simulate natural biological environments, physiological serum (solution of NaCl 9g /l) at pH=6.3, thermostatically controlled at 37°C was used as the electrolyte for the electrochemical tests. Analysis of the polarisation curves log(j)= f(E) showed that the titanium film/ AISI316L stainless steel provided better corrosion resistance and hence better biocompatibility than the substrate tested in the same conditions. In fact, the titanium formed a passive film over the entire surface that would be in contact with the human body. The results of the mechanical tests (microhardness, pull-off tests) showed that both materials meet the requirements for their use in implantology. Key words: stainless steel, titanium, corrosion, PVD, X-rays, microhardness, adhesion, biocompatibility, polarisation curves.