Abstract
For the purpose of improving the adhesion of polymer coatings to metal surfaces, composite substrate coatings of zinc containing phenol resin particles, originally suspended in the plating bath by using surfactants, have been proposed. The plating conditions, such as the concentration of suspended particles, current density, and relative velocity between the cathode and the electrolyte, which exert significant influences to the amount of particles contained in the composite films, have been investigated. Deposition of the resin particles is interpreted that the particles are initially adsorbed on the cathode by the electrophoretically, but only the particles strongly adsorbed by electrostatic force are embedded in the growing metal deposit, as shown in the Guglielmi's model. That is not the case, however, when the plating solution is vigorously agitated. The amount of particles codeposited in the composite film depends on the probability of the collision of particles with the cathode. From the values of bond strength and the observations of the surface by using SEM, the adhesion of polyethylene and polyamide layers to the composite substrate coatings are explained in terms of the increased surface area of phenol resin particles entrapped in the composite film surfaces, and the roughness of the composite surface.
