PLASMA AND ION-BEAM-ASSISTED DEPOSITION OF MULTILAYERS FOR TRIBOLOGICAL AND CORROSION PROTECTION

Multilayers of Ti/TiN and Al/AlN were deposited on steel and silicon b y magnetron sputtering and ion-beam-assisted deposition. Compositions and film thicknesses were determined by Rutherford backscattering. Har dness was measured with a dynamic ultramicrohardness tester. The corro sion protection potential in an aqueous environment was evaluated by e lectrochemical techniques. The results are discussed in terms of the s tructure and composition of the multilayer arrangement. It turns out t hat the multilayer coatings generally show a better corrosion protecti on performance than both the pure metal and the pure nitride films, wi th an optimum ratio of nitride film thickness to metal film thickness for a maximum corrosion protection effect. The hardness values are in between that of nitride single film and those of metal single films. D eposition of multilayers with the possibility of selecting the thickne ss ratio of metal to nitride film for particular mechanical and chemic al requirements allows a controlled adaption of the film features to a given application problem.