Ion beam mixing of thin films on nickel

Ion beam mixing of coatings has considerable potential as a technique for the modification of surface properties of materials used in hostile environments. In the present work ion beam mixing of Al, Hf, Y and Yb films on nickel using gaseous ion bombardment has been explored using Rutherford backscattering spectrometry and numerical analysis techniques developed for interpretation of the data. High dose N2+ bombardment of 600 A Al films on nickel at elevated temperatures was found to cause gas blister formation, with no unambiguous evidence of mixing. However, by using Ar+ ions and electrical heating, extensive mixing of 2000 A Al layers on nickel was observed. In elevated temperature Kr+ bombardments of Hf containing films, coating material was lost through sputtering, but some Hf was introduced into the substrate. The observed depth profiles indicated that irradiation induced segregation may have been responsible for the mixing. (author)