AUGER DEPTH PROFILES AND STUD PULL ADHESION OF METAL-FILMS ON GRAPHITE-EPOXY COMPOSITES

Ion beam depth profiling and Auger electron spectroscopy (AES) have be en used to characterize sputtered metal films on graphite epoxy compos ite substrates, with emphasis on elemental analysis of the interface b etween film and substrate. The AES data are correlated with adhesion s trength values, obtained by the stud pull method. Films studied includ e chromium, nickel, titanium, tantalum, platinum, and vanadium, deposi ted by RF planar diode sputtering in thicknesses from 0.5 micrometers to 1.5 micrometers on substrates of graphite epoxy composite (Fiberite 934). The AES/ion beam etch profiling technique was used to determine the atomic concentration of oxygen, carbon, and the deposited metal, from the outer surface through the depth of the film, into the substra te. Atomic concentration profiles are presented for each metal and cor related with adhesion strengths, substrate preparation, and sputtering conditions. High adhesion strengths for Cr and Ti films are associate d with elevated oxygen concentrations in the films, while the strong a dherence of Ni to graphite-epoxy is associated with very low oxygen co ntent. Lack of adhesion of Pt and Ta to graphite-epoxy is also associa ted with relatively low oxygen content in the metal/graphite-epoxy int erface. (C) 1997 Elsevier Science S.A.