Aluminum primer-epoxy layer

Adsorbed NTMP exhibits a pH-dependent surface coverage on anodized aluminum, which Includes a region characterized by a multilayer of hydrogen-bonded phosphonate molecules. These thick layers are weak and fall to provide good bond durability in a humid environment. NTMP monolayers are protective against hydration and are compatible with a nitrile-modified epoxy adhesive, but not with an epoxy-polyamide primer topcoat. 

First the metal base is washed with a solvent to remove any dirt, which could interfere with the binding process. The item is then blasted with minute particles of aluminum oxide, which create tiny pockmarks, greatly increasing the surface area. Then a primer, a mixture of Teflon and a binder, is sprayed on. The binder is a plastic, usually an epoxy, that sticks to the surface and provides a matrix in which the Teflon particles are embedded. This is heat cured, and then more layers of Teflon can be applied, because Teflon does stick to itself. Modern... 

Organic primers formulated with corrosion inhibitors are typically applied to pretreated metal surfaces to protect the surfaces prior to adhesive bonding and during environmental exposure. Pike [7-11] found that inorganic primers, such as sec-butyl aluminum alkoxide, improved the durability of aluminum-epoxy bonds when applied to both porous and nonporous aluminum oxide surfaces. It was shown that the effective thickness of the inorganic primer was directly related to the degree of oxide porosity and the depth of the porous oxide layer resulting from the normally used pretreatments for aluminum [10,11]. 

Heavy paint coating systems are used in severe atmospheres such as marine and industrial, and consist of a spray coating of zinc or aluminum, or a zinc-rich paint primer, followed by several layers of synthetic resin paints such as epoxy, tar epoxy, or polyurethane resins. The total film thickness is more than 250 jxm. 

The laminates consist of alternate layers of aluminum (0.2—0.5 mm thick), which has been anodized and then primed with Cytec-Fiberite s BR-127 corrosion-inhibiting primer, bonded together with fiber-rich, epoxy-based adhesive-prepregs (about 0.125 mm thick). The reinforcing fiber is usually unidirectional in nature, although woven fabric is occasionally used. Generally two or three sheets of adhesive separate each sheet of aluminum this can be in the 0° direction or laid up in a cross-plied orientation. 

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