NOVEL PHENYLETHYNYL IMIDE SILANES AS COUPLING AGENTS FOR TITANIUM ALLOY

摘要

Novel sol-gel solutions from new phenylethynyl imide silanes were applied to Ti-6-4 alloy to develop a surface for hot-wet environments. Silane concentration can be controlled by altering the molecular weight of the imide oligomer. The PPEIDS/TEOS sol-gel layer exhibited RT strength of 8800 psi with 95% cohesive failure and RT strength after a 3-day water-boil of 8108 with 91 % cohesive failure. SEM and AES depth profile revealed 1-2 μm thick sol-gel layer having higher Si concentration near the metal substrate, which may have contributed to the high strength and durability in the hot-wet environment. XPS and TGA data support that PETI-5/APEIS/TEOS or PPEIDS/TEOS solution forms a stable homogeneous hybrid structure at the interface to provide robust bonding. This provides a substitute for the conventional primer. These new sol-gel formulations can potentially be applied to any metal adherend for bonding with any phenylethynyl containing imide adhesive to provide stability for hot-wet environments without using chromium compounds and mechanical abrasion in the surface preparation.