Bonding of Aluminium

Authors from 3M [14] described the testing of two epoxy adhesives for aluminium designed for hem flange bonding and panel bonding. These adhesives showed outstanding sustained load durability in cyclic corrosion tests even if stressed to 40% of their initial shear strengths. 

Ford Research Laboratories [15] evaluated the fatigue behaviour of aluminium alloy joints and showed the enormous benefit of using an epoxy adhesive in combination with spot welding or mechanical 

As part of a US Army-sponsored programme, Martin Marietta Laboratories [17] conducted mathematical joint analysis and tested prototypes of tubular aluminium alloy joints bonded with a toughened adhesive. It is found that the tubes failed by tubular buckling at loads considerably lower than the expected limit load of the bonded joint. 

2 Bonding of Dissimilar Metals and Metals to other Substrates 

Japanese researchers [18] described a stress analysis of butt joints of steel to aluminium in which joints were assembled with epoxy adhesives and subjected to cleavage loads. They found that the normal and shear stresses were maximised at the edge of the interface on the load application side between the substrates and the adhesive bond. However, both stresses were greater at the edge of the interface between the higher-modulus substrate (steel) and the bond. 

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Current usage is almost entirely associated with the good adhesion to aluminium. Specific applications include the bonding of aluminium foil to plastics films, as the adhesive layer between aluminium foil and polyethylene in multilayer extrusion-laminated non-lead toothpaste tubes and in coated aluminium foil pouches. Grades have more recently become available for manufacture by blown film processes designed for use in skin packaging applications. Such materials are said to comply with FDA regulations. 

Shields, J. Adhesives Handbook, 3rd Edition. Butterworths, London, 1984. T1 Thrall, E. W. Shannon, R. W. Adhesive Bonding of Aluminium Alloys. 

The bonding of aluminium alloy components for structural engineering applications has been the subject of extensive research by the Dutch TNO Institute for Building Materials and Structures(19, 20). Apart from the evaluation and testing of a number of adhesive systems, experimental research was carried out on several structural details. Aluminium alloy surface pretreatment was by degreasing only, to represent a practical procedure. 

Typical Use General purpose. Bonding of aluminium and other metals, ... 

Water-borne primers have been evaluated [25]. Davies and coworkers [26] described the improvement in adhesive bonding of aluminium alloys by anodising before bonding. This work showed that the morphology of the oxide and penetration of the adhesive into the porous oxide strongly influences bond performance. 

Figure 1.19 Adhesives are widely used in the construction of many civil engineering projects, such as the bonding of aluminium panels. 

Allen KW (1977) Surface preparation of a stainless steel for adhesive bonding. J Adhes 8 183 Arrowsmith DJ, Clifford AW (1985) A new pretreatment for the adhesive bonding of aluminium. Int J Adhes... 

Crithlow G, Yendall KA, Bahrani D, Quinn A, Andrews F (2006) Strategies for the replacement of chromic acid anodising for the structural bonding of aluminium alloys. Int J Adhes Adhes 26 417 David GL (1974) Adhesive joining of stainless steels. Pt. 2. Met Deform 26 45... 

Guyott CCH, Cawley P, Adams RD (1986) The nondestructive testing of adhesively bonded structure a review. J Adhesion 20 129-159 Guyott CCH, Cawley P, Adams RD (1987) Use of the Fokker bond tester on joints with varying adhesive thickness. Proc IMechE 201(B1) 41—49 Hagemaier DJ (1985) Adhesive bonding of aluminium alloys. Marcel Dekker, New York Hart-Smith LJ, Thrall EW (1985) Adhesive bonding of aluminium alloys. Marcel Dekker, New York, pp 241—335... 

Fig 3. Predicted electro-acoustic response for PVDF film bonded to aluminium and backed with different thicknesses of copper. (Thicknesses shown in pm.)... 

In this molecule, the aluminium receives a pair of electrons from the nitrogen atom. The nitrogen atom is referred to as a donor atom and the aluminium as an acceptor atom. Once the bond is formed it is identical to the covalent bond of previous examples it differs... 

All the other aluminium halides are covalently bonded with aluminium showing a coordination number of four towards these larger halogen atoms. The four halogen atoms arrange themselves approximately tetrahedrally around the aluminium and dimeric molecules are produced with the configuration given below ... 

Many of the most floppy polymers have half-melted in this way at room temperature. The temperature at which this happens is called the glass temperature, Tq, for the polymer. Some polymers, which have no cross-links, melt completely at temperatures above T, becoming viscous liquids. Others, containing cross-links, become leathery (like PVC) or rubbery (as polystyrene butadiene does). Some typical values for Tg are polymethylmethacrylate (PMMA, or perspex), 100°C polystyrene (PS), 90°C polyethylene (low-density form), -20°C natural rubber, -40°C. To summarise, above Tc. the polymer is leathery, rubbery or molten below, it is a true solid with a modulus of at least 2GNm . This behaviour is shown in Fig. 6.2 which also shows how the stiffness of polymers increases as the covalent cross-link density increases, towards the value for diamond (which is simply a polymer with 100% of its bonds cross-linked. Fig. 4.7). Stiff polymers, then, are possible the stiffest now available have moduli comparable with that of aluminium. 

The hydrides of the later main-group elements present few problems of classification and are best discussed during the detailed treatment of the individual elements. Many of these hydrides are covalent, molecular species, though association via H bonding sometimes occurs, as already noted (p. 53). Catenation flourishes in Group 14 and the complexities of the boron hydrides merit special attention (p. 151). The hydrides of aluminium, gallium, zinc (and beryllium) tend to be more extensively associated via M-H-M bonds, but their characterization and detailed structural elucidation has proved extremely difficult. 

Alclad a composite in which a thin layer of aluminium, or an aluminium alloy of good corrosion resistance, is bonded metallurgically to a high-strength aluminium alloy (of lower corrosion resistance) to provide a combination of these two properties. 

Burg, A. B., and K. Modritzer Chemistry of Phosphorus Aluminium Bonding Dimethylphosphino-Aluminium Hydrides and Chlorides. J. Inorg. Nucl. Chem. 13, 318 (1960). 

Clays consist of parallel silicate layers in kaolinite, two unsymmetrical types of layers are linked by hydrogen bonds. One consists of aluminium ions and hydroxyl groups, the other of silicon and oxygen ions. Cairns-Smith does not postulate a detailed mechanism, but only describes the main thrust of his argument. Critics complain that clear experimental results are not available (however, other proponents of new hypotheses often provide no evidence to back up their suggestions ). 

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