Chemical and Thermodynamic Characterization of Metal Surfaces for the Adhesive Bonding of Metals

Abstract

Several complementary surface analysis techniques were employed to determine the properties of the polished surfaces of titanium-6Al,4V, 2024-T3 aluminum, and interstitial free steel. XPS indicated that the oxides were all approximately 50 Å thick and covered with a layer of carbon-containing compounds probably consisting of both hydrocarbons and more highly oxidized carbonaceous materials such as carbonates or bicarbonates. The calculation of wettability envelopes showed all of the surfaces to have similar energetics, possibly because these properties are determined largely by the adsorbed water and hydrocarbons present on all transition metal surfaces. The surface isoelectric points were estimated using indicator dyes and compared to published values. Finally, reflection-absorption infrared spectra were obtained from the aluminum surfaces, allowing the oxide structure to be determined and giving more information about the nature of the overlying carbon-containing compounds.