Adhesion phenomena involving polymer-metal interfaces have become a central subject for research and technological development, especially in view of adhesive bonding of metallic components in primary load-bearing structures. Since adhesion implies that some sort of chemical and/or physical interactions take place between the metal adherend and the polymeric adhesive, a great deal of attention has been devoted to identification and characterization of such interactions and to the development of techniques to study them. Among the most widely used methods for interfacial studies are: ESCA (Electron Spectroscopy for Chemical Analysis), AES (Auger Electron Spectroscopy), SIMS (Secondary Ion Mass Spectroscopy), IR spectroscopy, optical microscopy, and electron microscopy.

Les mesures de profils des depots electrolytiques d'etain-plomb revelent des excroissances laterales et au sommet. Ces caracteristiques ont des implications importantes quand le procede de depot selectif est utilise pour des dispositifs en microelectronique

The oxides formed on Al-1100 by chromate conversion, chronic acid and sulfuric acid anodizing were characterized, prior to (as previously published) and after exposure to hygrothermic environments, by spectroscopic methods. The suitability of adhesive bonding and durability accomplished with silicone rubber were evaluated by shear bond strength and by the locus of failure using single lap joints and SEM/EDAX, respectively. Results from Auger/ESCA and IR have shown that in the exposed oxide layers the oxygen concentration increased due to water absorption, leading to transformation from oxide to hydroxide. In the case of chromic acid anodizing, which gave the optimal bonding performance, the reverse occurred regarding oxygen concentration while IR results showed water absorption.

A study was made to characterize the surface of oxides formed on Al 2024 in comparison to those formed on Al 1100, using Auger, ESCA, SIMS, FTIR and SEM/EDAX techniques. The pretreatments studied were chromate conversion coating, chromic acid anodizing and sulfuric acid anodizing. The specimens were evaluated as treated and after exposure to laboratory conditions (T=25≠3°C and relative humidity of 60≠10%) for 6 months. In addition, a new surface pretreatment was studied, which was based on McDonnell Douglas P.S. 13201 specification. Adhesive bond strength of silicone rubbers and epoxy adhesives to pretreated Al 2024 was determined, using single lap joint specimens. It was shown that the main difference between the anodic coatings on Al 1100 and Al 2024 was the presence of copper on the surface in the latter. The presence of copper led us to postulate the mechanism of polymerization inhibition of 2 parts polysiloxane adhesive. The most suitable treatments for adhesive joining were found to be chromic acid sealed or unsealed anodizing for both Al 2024 and Al 1100. Our standard chromic acid anodizing gave higher bond strength for aluminum-adhesive joints than the “Douglas” process. as determined with several epoxy adhesives. Correlation between microscopic and macroscopic phenomena was established.

In the present work chemical interactions between sealed chromic-acid-anodized or conversion-coated Al1100, two proprietary primers and PR-420, a polyurethane adhesive, were studied. The chemical compositions of the primers and the adhesive were determined. All the relevant combinations of substrate-primer-adhesive were evaluated, using FTIR, Auger and SIMS spectroscopies. Single lap joint shear strength of the various combinations served as an indicator to the preferred surface treatment for a sound adhesive bonding. Chromic acid anodizing with a commercial AD-6 primer gave the best results. Correlation between chemical interaction and bond strength was observed.

A study was made to characterize by spectroscopic methods the surface of oxides formed on Al 1100 by chromate conversion coating, chromic acid anodizing and sulfuric acid anodizing. Adhesive bond strength to silicone rubber was determined using single lap joint specimens, and correlation between the microscopic structure and macroscopic values was found. It was observed that the layer formed in chromate conversion coating was essentially hydrated chromia, and it yielded the lowest bond strength. Sulfuric acid anodizing produced hydrated alumina, incorporating sulfate ions in its matrix; an intermediate bond strength was found with this pretreatment. Chromic acid anodizing gave rise to a compact, almost anhydrous alumina film, and the highest bond strength was attained.

Chemical interactions in the primed aluminium/adhesive interphase were examined using IR reflectance spectroscopy. For the case of epoxy primers and polyurethane adhesives, a new absorption was detected and was attributed to an isocyanate group, formed by reaction between the epoxide primer and the polyurethane adhesive. When polyurethane adhesive was applied on a polyurethane primer, such a primer-adhesive interaction was not noticed.

AbstractA study was made on the influence of sulphuric and chromic acid anodizing on the polymerization behavior of four primers (three based on epoxy resins and one on polyurethane) using IR and AES spectroscopy. AES spectroscopy has revealed that sulphur anions were incorporated in the anodic film, but no chromium anions could be detected. IR spectra for the primers on chromic acid anodic films are similar to those obtained on untreated aluminium, but a change of absorption peaks was observed for sulphuric acid anodic film substrate. Sulphuric acid anodizing has an adverse effect on the polymerization of the primers studied in this work.

Specimens of pure Ti and Mo, as well as 250 grade maraging steel, were heat treated in superheated steam at 485°C for 3 h. The composition profiles and binding energies were studied, using AES and ESCA techniques. It has been shown that the mechanism of oxide formation is that of cation migration.

The microstructure of oxides formed on 250 maraging steel in steam at elevated temperatures was established. The coating consisted of at least two sub-layers, an innermost layer of austenitic phase and a layer of magnetite Fe3O4. When low loads of steel were used, a third top layer of hematite Fe2O3 was found. The coating provides good protection against atmospheric corrosion, which was significantly better than phosphating.

A mechanism of oxide film growth via outward iron cation migration during thermal oxidation of Fe-Ni-Co alloys in air, steam and carbon dioxide at 485°C is suggested. This mechanism is supported by literature data, and experimental results obtained by Auger electron spectroscopy and depth profile determination, SEM-XES analysis and X-ray diffraction.

AbstractEs wird ein Doppelschichtmodell für anodische Schichten vom Sperrtyp auf Aluminium vorgeschlagen.

A duplex-film model for barrier anodic films on aluminium is suggested, the lower layer being homogeneous and amorphous and the upper consisting of a dispersion of a crystalline phase in an amorphous matrix. From impedance measurements over a range of frequencies, the dielectric constants of the layers are estimated as 12 and 9 respectively.

"Electrodeposition of Nickel on Tantalum Part II: Crystallographic Structure." Transactions of the IMF, 49(1), p. 42

Optical and electron microscope examinations have been carried out on anodic oxide films formed on aluminium in H3BO3/Na2B4O7 solutions under various temperature and formation voltage conditions. Whereas at low temperatures and voltages a barrier type of film was produced, an increase in either parameter encouraged crystallization and porosity.

An anodizing process using 0·1–2·5% HBF4 at 0–30°C has been developed, for pure Al and Al alloys. The film formed at high c.ds. has a high breakdown voltage/thickness ratio: surface area measurements using the BET method and electron microscopy suggest that the film formed is of a porous/barrier type.