A protective coating adhered to the surface of a metal substrate such as a pipe using an adhesive composition containing an adhesive component and a polyhydroxy compound protects the substrate from corrosion. The adhesive has improved resistance to cathodic disbonding which generally weakens the adhesive bond between the protective coating and the substrate when a current is impressed through the substrate causing it to function as a cathode. The electric current inhibits loss of metal ions from the substrate to the environment thus reducing corrosion of the substrate.