Surface Pretreatment of Zinc and its Adhesion to Epoxy Resins

Abstract

An epoxy resin based on the diglycidyl ether of bis-phenol A cured with piperidine and containing 7 or 15% rubber toughening agent has been bonded to zinc and the adhesion measured by calculating the critical strain energy release rate, Gc, from single edge notched (SEN) and tapered double cantilever beam (TDCB) specimens. The zinc has been pretreated to give surfaces ranging from relatively flat to “microfibrous” ones covered with dendrites of the metal. The microfibrous surfaces give highest values of Gc with both modified and unmodified resins. The fracture surfaces have been studied with SEM, XPS and EPMA and the failure mode related to the joint toughness.