The bond strength of composite articles of rubber adhered to ferrous metal substrates through an adhesive is substantially improved at ambient and elevated temperatures by depositing a specified amount of a layer of copper on said ferrous metal substrate, applying an adhesive thereover comprising an interpolymer containing about 50 to about 99% by weight of a conjugated diene, about 1-45% by weight of a heterocyclic base and 0 to about 40% by weight of at least one additional copolymerizable monomer, thereafter contacting said adhesive with the rubbber to be bonded and bonding by heat and pressure.