Durability of adhesion between metals and polymers.

Adequate adhesion between metals and polymers is primarily the result of chemical bonds in the boundary layer. This region, however, is subject to degradation by moisture. Three models of degradation are observed. The first is a largely reversible weakening effect in the polymer layer near the metal oxide surface. The structure of this layer differs from that of the bulk and is influenced by the chemical and physical properties of the surface. The second is a slow transformation of the oxide by hydration and a diffusion of oxide constituents into the polymer. The third is a fast deterioration of the oxide by primary corrosion.