Technical and functional properties of some biocompatible thin films

The technical and functional characteristics of some biocompatible, thin, double-layer films (of different compositions; the first layer: Ag30–Cr70 or Co30–Cr70 alloy or stainless steel and the second layer: TiN) on rare-earth-based permanent magnet alloy (Nd30–Dy5–Fe–Al0.4–B) proposed to be used as dental materials have been investigated. Data about electrochemical behaviour, wear resistance and adhesion are presented. The electrochemical behaviour of these films was determined in artificial saliva, using the electrochemical potentiostatic polarisation and electrochemical impedance spectroscopy techniques. The wear behaviour in different conditions of contact and load was tested and the adhesion was determined by scratching test. It resulted that the tested films presented passivation tendency and a very good stability, and no form of local corrosion was detected. The electrochemical behaviour of these films is described by an equivalent circuit with two time constants. The wear resistance is very good. The films own a very good adhesion, which is proper for the proposed purpose.