Mechanical Properties of Adhesively Bonded Aluminum Structures Protected with Hydrated Inhibitors.
Rept. for 1 Jul 80-30 Jun 81,
MARTIN MARIETTA LABS BALTIMORE MD
Pagination or Media Count:
Our research has shown that the adsorbed monolayer inhibitor films that slow the conversion of Al-oxide to hydroxide substantially improve the bond durability of 2024Al adherends prepared with the Forest Products Laboratory process FPL. In particular, an inhibitor coating of nitrilotris methylene phosphonic acid produced a bond durability in adherends prepared with the FPL process that was nearly the same as that in samples prepared with the otherwise more durable phosphoric acid anodization process PAA. As determined by x-ray photoelectron spectroscopy, the inhibitor coverage needed to produce the maximum improvement in bond durability was approximately one monolayer. Increase in coverage above the presumed monolayer value did not produce better durability. Surface treatment with phosphoric acid rather than phosphonic acid was ineffective in producing better durability of adherends prepared with the FPL process. Analysis of the results suggests that a compounds effectiveness in improving bond durability of adherends prepared with the FPL process depends on both its ability to inhibit the conversion of Al-oxide to hydroxide and to form chemical bonds with the adhesive. Author
- Adhesives, Seals and Binders
- Properties of Metals and Alloys