|
3874 |
|
Friday, May 23, 2014, Hall H1 11:20 AM Corrosion Protection |
|
Novel environmentally-friendly coatings for aerospace alloys |
|
Janette Harris* / University of Manchester, U.K. Xiaorong Zhou / University of Manchester, U.K. George Thompson/ University of Manchester, U.K. Phil Scott/ Airbus, U.K. |
|
The aim of this research is to develop environmentally-friendly alternatives to current practice for the corrosion protection of aerospace alloys since the environmental impact of the deposition processes and the susceptibility of high strength steels to hydrogen embrittlement require the development of new coatings. In the present study, coatings of aluminium, zinc and combinations of aluminium-zinc and zinc-nickel were applied to steel substrates using the cold gas spray process. The coatings were examined using optical, scanning and transmission electron microscopies to evaluate through coating microstructure and composition. Significant plastic deformation of metal grains was evident. Further, it was revealed that the uniformity and compactness of the coatings are directly associated with the shape and size of the metal powders for coating, and the gas pressure and temperature. The composition of the multi-component coatings was found to differ substantially from the initial mixed feedstock powder. Two post coating treatments of tartaric acid/sulphuric acid anodising and SurTec 650 chromitAL® passivation were selected and applied to the cold sprayed aluminium coatings to improve corrosion resistance. The performance of the coatings is currently being evaluated and compared with ion vapour deposited and electrodeposited coatings. |