Effect of metal surface state on injection joining strength of aluminum-rubber composite part

Abstract

Metal–rubber composite parts with characteristics of high elasticity and compressibility are widely used in seal and vibration resistance engineering fields. The injection technology was proposed to mold metal – rubber composite parts. With pretreatments of anodization and silane coupling agent, the morphology and composition of Al surface were changed, and then Al - rubber composite parts were fabricated by injection technology. The effects of Al surface morphologies and compositions induced by different conditions of anodization and coupling agent were discussed. The scanning electron microscopy (SEM) and X-ray energy spectrum analyser (XPS) of Al surface examination proved that microstructures and hydroxyl groups formed on the metal surface contribute significantly to the bonding strength of the Al - rubber interface. Furthermore, the effect of metal temperature on the bonding strength between the rubber and the Al was investigated. By increasing the metal temperature to 120 °C, the bonding strength improved by more than twenty folds compared to the lower temperature case. Results showed that the molded composite parts exhibit excellent tensile shear strength, exceeding the shearing strength of the rubber itself. The presented method can be promoted in related engineering fields.