Surface Modification for Improved Adhesive Bond Durability on Galvanized Steel

The use of adhesives for bonding thinner galvanized steel automotive body parts is increasing. Associated with the use of adhesives is adhesive bond durability. Adhesive bond durability can be improved by chemically modifying the surface of galvanized steel. Five surface modifiers, each representing a different chemical class, were found to enhance adhesive bond durability of galvanized steel to an epoxy adhesive as demonstrated by environmental unstressed and stressed adhesively bonded lap shear durability tests. The observed durability improvements are attributed to interfacial chemistry changes resulting from surface modification that occurs between the adhesive and adherend.