Warm water treatment of aluminum for adhesive bonding

The effectiveness of treating grit-blast aluminum 2024 and 7075 alloys with a warm water treatment prior to the application of a silane solution as part of the surface treatment for adhesive bonding has been investigated. At 50°C, treatment times in excess of 30 min resulted in joints which showed negligible crack growth in the wedge test performed at 50°C and 95–100% RH. At 40°C, a treatment time of at least 1 h was required in order to obtain comparable performance. The results extend previous work done with boiling water.