The Durability of Epoxy Adhesive Bonds formed with Titanium Alloy

The durability of adhesive bonds formed between titanium alloy (Ti-6Al-4V) and rubber toughened epoxy structural adhesives used for repair bonding applications was examined. Two surface treatments were studied; the grit-blast and silane method, currently employed for titanium repairs on F-111 at RAAF Amberley and the F/A-18 SRM method which uses Pasa-Jell 107, a proprietry based toxic chemical treatment. Results from wedge style durability tests indicated the grit-blast and silane pre-treatment provided notably better performance than the Pasa-Jell 107 pre-treatment for epoxy bonds formed with Ti-6Al-4V alloy. Addition of BR127 primer to the pre-treated surfaces did not offer substantial improvement in durability performance. The durability of titanium-epoxy adhesive bonds for the grit-blast and silane pre-treatment on titanium was inferior to the performance observed on aluminium alloys. Further research will be required to improve the performance of the grit-blast and silane treatment on titanium to levels observed for aluminium