Structural Technology and Analysis Program (STAP). Delivery Order 0010: Sol-Gel Technology for Surface Preparation of Metal Alloys for Adhesive Bonding and Sealing Operations

摘要

This report summarizes the development efforts to devise prebond surface preparations and hybrid primers utilizing sol-gel technology on aluminum, titanium, and steel substrates. The project focuses on the development and optimization of user-friendly sol-gel methods for preparing metal surfaces for bonding with 250 F-cure and 350 F-cure epoxy adhesives. Significant progress has been made in developing user-friendly sol-gel surface preparation methods for repair and original equipment manufacturing (OEM) bonding. The surface preparations developed also showed feasibility as adhesion promoters for sealants. Surface treatment systems were developed using sol-gel chemistries and the processes to use these materials were optimized. Non-grit-blast methods of deoxidation were devised that work well on aluminum alloy surfaces. Round robin testing and design of experiment methodologies were used to ascertain the robustness of the processes. Several component demonstrations were conducted in the field to obtain data from the end-user community. Surface characterization and molecular modeling techniques were employed to assist in the optimization of the interactions between metal substrates and sol-gel coatings. The results of these studies, including bond performance and durability, depot-level and field testing, sol-gel kitting schemes, surface characterization, and implementation and technical transfer status, are summarized in this report.