ION-BEAM MIXING OF AL-ALN MULTILAYERS FOR TRIBOLOGICAL AND CORROSION PROTECTION

The changes of the tribological and corrosion protection properties of Al-AlN thin film multi-layered structures ''posed to 1.8 MeV Ar+ ion bombardment were studied. The Al-AlN multilayers used in this study ha d periodic thicknesses ranging from 25 nm/100 nm Al/AlN to 100 nm/25 n m Al/AlN before the bombardment. Ion beam mixing was accomplished by i rradiations with relatively low dose and current density (1 x 10(16) A r+ cm-2;1 muA cm-2). The composition and layer sequence was derived fr om Rutherford backscattering and Auger electron spectrometric measurem ents. The-corrosion protection potential of the coatings was evaluated by electrochemical methods. The hardness was measured with a dynamic ultramicrohardness tester. It could be shown that ion bombarded multil ayers consisting of sequences of 30 nm Al and 100 nm AlN (30/100 thick ness ratio) gave the best results as long term corrosion protection an d adhesion are concerned. The hardness of these samples was only sligh tly lower than the one of a single layer AlN film. Therefore these ion beam mixed multilayers represent a new class of protective coatings w ith excellent properties.