Silane based field level surface treatment methods for aluminium, titanium and steel bonding

Grit blast silane and AC-130 sol–gel treatments were tested to assess their performance in aluminium, titanium and stainless steel structural epoxy bonding. Static single lap shear and static double lap shear specimens were tested as dry and wet at room temperature. Wedge tests were performed in a hot and wet exposure and in hot fresh water and salt water immersions. Acceptable field level methods were found for unclad and clad 7075 aluminium bonding without primers. With titanium and stainless steel, the use of a BR 6747-1 primer was found to be necessary for durable adhesion. In a case study, AC-130 sol–gel without a primer on naval grade 5083 aluminium provided good results also when immersed in Baltic Sea water.