A STUDY OF BRASS SQUALENE INTERFACIAL COMPOSITIONS USING SURFACE ANALYTICAL TECHNIQUE

A model system using squalene has been reacted with sulphur, accelerators etc. against a cleaned brass surface without and in the presence of adhesion promoters based on cobalt. The interfacial layer found to exist between the purely organic material and the metal substrate has been examined by XPS/ESCA and SIMS after successive periods of ion etching. The interfacial interlayer proceeds from being almost entirely organic through a mixed organic/metal sulphide layer to copper sulphide with some zinc sulphide, then zinc oxide and finally to the bulk metal of the substrate. Cobalt compounds are carried into the copper sulphide there forming cobalt sulphide. There are subtle differences of behaviour between cobalt-MBT, cobalt neodecanoate and cobalt boroacylate. The latter seems to be more closely associated with the copper sulphide than other materials investigated. The effect of steam ageing is briefly considered. © 1990, Taylor & Francis Group, LLC. All rights reserved.