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Novel Chrome-Free Bonding Primer for Structural Bonding and Corrosion Protection in Aerospace Applications


Title: Novel Chrome-Free Bonding Primer for Structural Bonding and Corrosion Protection in Aerospace Applications

Authors: Alexander Peetsch, Claudia Blaffert, Christian Ramm, Martin Renkel, Ruairí O’Kane, Bryce Floryancic, Michael Frank, Omar Abu-Shanab

DOI: 10.33599/nasampe/s.21.0514

Abstract: Aluminum parts in the aerospace industry require specific surface coatings that provide long-term corrosion protection and facilitate bonding performance towards adhesives. These coatings are known as bonding primers. For decades, strontium chromate was used as a corrosion inhibitor in bonding primers to effectively protect aluminum alloys. Despite its outstanding anticorrosive properties, its acute toxicity, carcinogenicity, and mutagenicity made it subject to regulatory restrictions and usage bans (e.g. REACH). Therefore, the aerospace industry seeks for sustainable and less toxic alternatives. This technical paper discusses the development of a waterborne, chrome-free bonding primer based on epoxy chemistry. The paper discloses the application characteristics, cure behavior and film formation on aluminum surfaces. Surface characterization techniques such as SEM and GDOES were used to reveal the interaction with aluminum surfaces and film adhesives. Chemical resistance and corrosion protection performance are discussed by means of fluid immersion, wipe resistance and corrosion testing techniques. Bonding properties were tested in conjunction with Henkel film adhesives. The findings revealed that this novel chrome-free bonding primer can effectively protect aluminum surfaces from corrosion and promote adhesion towards aerospace structural adhesives to replace strontium chromate bonding primers.

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Conference: SAMPE NEXUS 2021

Publication Date: 2021/06/29

SKU: TP21-0000000514

Pages: 14

Price: FREE

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