Session Details

Session 1: Aerospace/Defense Response to REACh

Abstract Number:

94

This talk focuses on development of the next generation of sol-gel ‎pretreatments, i.e. sol-gel pretreatments with added corrosion ‎protection for aerospace Al alloys.‎

Topics:

Advances in Surface Finishing Technology

Corrosion protection of aerospace alloys has traditionally relied on the use of hexavalent ‎chromium conversion coatings (CCC). However hexavalent chromium is a carcinogen and is ‎toxic to the environment. Elimination of hexavalent chromium from conversion coatings, ‎primers and processes will enable worker safety, enable cost avoidance by eliminating use of ‎hazardous chemicals, baths and wastes and allow Boeing to be REACH, OSHA and EPA ‎regulation compliant.‎

Boegel is an organo-silane based adhesion promoter qualified to BMS10-128 and primarily ‎used on clad aluminum skins of the 737, 747, 767 and 777 aircrafts. The use of Boegel on ‎these platforms eliminated the use of chromate conversion coatings on the exterior surface ‎of the aircrafts and helped solve the rivet rash problems caused by poor paint adhesion to ‎aluminum rivets.‎

Boegel EPII (commercially available as AC131 from 3M) was originally designed to enhance ‎bond adhesion to aluminum surfaces and adhesion to subsequent epoxy primers, however ‎provided no sacrificial standalone corrosion resistance to the base substrate. This study ‎details investigating the addition of corrosion inhibitors to Boegel (corrosion resistant Boegel ‎or CRB) to provide an extra layer of corrosion protection adjacent to the metal surface ‎without compromising paint adhesion. Corrosion resistance of CRB was evaluated with best ‎performing non-chromate primers from PPG, Akzo Nobel, Hentzen and Av-Dec and a PPG ‎polyurethane topcoat. The corrosion performance of CRB was also compared to standard ‎sol-gel (AC-131 from 3M), Alodine 1200, Alodine 5200 and SurTec 650V pre-treatments. ‎

CORROSION RESISTANT BOEGEL AS A NON-HEXAVALENT ‎CHROMIUM PRETREATMENT

Vivek Kapila

Engineer

Boeing

Waynie Schuette

Engineer

Boeing