IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Applied Surface Analysis Thursday Sessions
       Session AS-ThA

Paper AS-ThA10
Adsorption of Organic Acids onto the Surface of 2024-T3 Aluminium Alloy: The Role of Intermetallic Particles

Thursday, November 1, 2001, 5:00 pm, Room 134

Session: Adhesion and Corrosion
Presenter: A.J. Roberts, Kratos Analytical Ltd., UK
Authors: A.J. Roberts, Kratos Analytical Ltd., UK
D. Engleberg, UMIST, UK
Y. Liu, UMIST, UK
G.E. Thompson, UMIST, UK
M.R. Alexander, UMIST, UK
Correspondent: Click to Email
Self-assembled monolayers of alkyl-phosphonic and carboxylic acids have been proposed as alternatives to conventional chrome-based pre-treatments for corrosion protection of aluminium. These organic pre-treatments aim to form coupling layers between the air-formed aluminium surface and the resin component of paints and adhesives.@footnote 1@ Commercial aluminium alloys contain intermetallic particles which mechanical and chemical finishing processes may expose at the surface.@footnote 2@ Analysis is complicated by the size of the particles that can range from 0.1-10µm. Auger analysis has suggested preferential adsorption of long chain phosphonic acids at iron-containing inclusions in an AlMg1 alloy, although no chemical state or quantitative information was presented.@footnote 3@ Small area and imaging XPS, with a Kratos Axis Ultra spectrometer, has been used to obtain quantitative elemental and chemical state information from such particles (Al@sub 2@Cu and Al@sub 2@CuMg) at the mechanically polished surface of Al 2024-T3, an alloy of importance in the aerospace industry. Alkyl-phosphonic and -carboxylic acids were adsorbed from dilute solutions allowing comparison of coverage and chemical state between the second phase intermetallics and the hydrated alumina surface of the matrix. Comparison is also made with the adsorption characteristics on super pure Al.@footnote 4@ Polarisation modulation IRRAS provides complimentary information on the interfacial bonding and degree of order within the monolayers. @FootnoteText@ @footnote 1@I Maege et al. Macromol. Symp. 126 (1997) 7.@footnote 2@I Pires et al. Transactions of the Institute of Metal Finishing 78 (2000) 179. @footnote 3@Ch. Bram et al. Fresenius J Anal Chem 358 (1997) 108. @footnote 4@ TA Lewington et al. Comparison of alkyl-carboxylic and phosphonic acid monolayer formation on Al, in preparation for submission to Surf. Interface Anal.