DEPOSITION OF CORROSION-RESISTANT CHROMIUM AND NITROGEN-DOPED CHROMIUM COATINGS BY CATHODIC MAGNETRON SPUTTERING

This work deals with the realization of corrosion-resistant chromium-b ased thin films by cathodic magnetron sputtering. A systematic study o f the deposition parameters (substrate temperature, pressure and gas m ixture composition) has been carried our to determine the optimal cond itions to obtain films with good corrosion resistance and also with go od mechanical properties such as hardness, wear resistance and adhesio n. The structure of the films has been determined by X-ray diffraction and their composition by X-ray photoelectron spectroscopy. The corros ion resistance of the samples has been characterized by an electrochem ical method with a potentiostat and a synthetic sweat test. It is show n that the substrate temperature has a great effect on the film struct ure and texture. Appropriate doping with nitrogen makes it possible to increase the coating density and decrease the grain size, with a corr esponding improvement in the corrosion resistance of the films. This d oping also allows us to improve the microhardness up to 35 GPa.