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Novel methods, incorporating pre- and post-anodising steps, for the replacement of the Bengough–Stuart chromic acid anodising process in structural bonding applications
journal contribution
posted on 2009-03-31, 12:07 authored by Keith YendallKeith Yendall, Gary CritchlowThe present investigation focuses on novel anodising processes which are
being developed for the replacement of the hexavalent chromium containing
40/50V Bengough-Stuart process, with particular emphasis on their resultant
performance in structurally bonded systems used in the demanding and harsh
environments encountered on operational aircraft. An electrolytic phosphoric
acid based deoxidiser (EPAD)has been studied in combination with a standard
sulphuric acid anodise. It has been shown that the EPAD provides an open
porous structure in order to enhance adhesion to the modified sulphuric acid
anodised (SAA) surface. Additionally, a post anodising (PAD) treatment has
been used to aid structural adhesion in combination with the SAA processes.
2
As a control, the standard 40/50V Bengough-Stuart chromic acid anodising
(CAA) has been used as a baseline performance indicator in adhesion tests.
Single lap shear (SLS) and modified Boeing wedge tests were used to
determine adhesion performance. SLS tests were used to determine initial, dry
joint strengths whilst wedge test joints immersed in deionised water for up to
100 hours gave a measure of joint durability. Overall, excellent initial joint
strengths and durability have been found with both EPAD plus SAA and PAD
plus SAA processes suggesting that these environmentally benign treatments
may be used as possible drop-in replacements for the currently used
hexavalent chromium process. Electron microscopy has been used to
investigate the topographical changes introduced to the surface by the various
surface pretreatments under investigation to provide an explanation for the
observed adhesion test results.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Citation
Yendall, K.A. and CRITCHLOW, G.W., 2009. Novel methods, incorporating pre- and post-anodising steps, for the replacement of the Bengough–Stuart chromic acid anodising process in structural bonding applications. International Journal of Adhesion and Adhesives, 29 (5), pp. 503-508Publisher
© ElsevierVersion
- AM (Accepted Manuscript)
Publication date
2009Notes
This article was published in the journal, International Journal of Adhesion and Adhesives [© Elsevier]. The definitive version is available at: http://www.sciencedirect.com/science/journal/01437496ISSN
0143-7496Language
- en