Al-Mn Thermally Sprayed Coatings as Replacement of Cd-Based Coatings

Abstract:

Cadmium coatings are used in aerospace and offshore industries for parts in corrosive environments. Since cadmium is a highly toxic heavy metal, it is subject to strong restrictions. Alternatives include Al-based alloys. The present work describes preliminary results for Cd substitution by using Al-Mn with 25 at.-% Mn deposited on 42CrMo4 steel by atmospheric plasma spraying (APS). The prepared alloy powder for the APS process was characterized by laser granulometry, SEM/EDX, and STA. A fraction with particle sizes ranging from 20 µm to 45 µm was used for the thermal spraying process. The APS coating and an Al reference sample were characterized by image analysis, Vickers hardness, and Standard Salt Spray (SSP) testing. The Al-Mn coating exhibits a significantly higher hardness in comparison to pure Al. In both cases, red iron corrosion did not appear during SSP testing. The Al coating was partially covered by a thick oxide film, whereas Al-Mn showed only moderate oxidation but lower adhesion to the substrate

• Periodical: Materials Science Forum (Volumes 825-826)
• Pages: 613-620
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.825-826.613
• Online since: July 2015
• Authors: Andrea Förg*, Gerhard Wolf, Klaus Dotzler, Laure Libralesso, Patrick J. Masset
• Keywords: Al-Mn Alloy, Cadmium, Corrosion, Powder, Thermal Spraying

References

[1] A. Conde, M.A. Arenas, J. de Damborenea, Electrodeposition of Zn-Ni coatings as Cd replacement for corrosion protection of high strength steel, Corr. Sci. 53 (2011) 1489-1497.

DOI: 10.1016/j.corsci.2011.01.021

[2] M. Silomon, C.V. Bishop, P. Wynn, Werkstoffliche Betrachtung von galvanischen Zink- und Zinklegierungsüberzügen und deren Nachbehandlungen, Galvanotechnik 91 (2001) 2932-2939.

[3] F. Torres, M. des Graças, M. Melo, A. Tosti, Management of contact dermatitis due to nickel allergy: an update, Clin. Cosmet. Investig. Dermatol. 2 (2009) 39-48.

DOI: 10.2147/ccid.s3693

[4] M. Bielewski, Replacing cadmium and chromium, in: RTO-AG-AVT-140 – Corrosion Fatigue and Environmentally Assisted Cracking in Aging Military Vehicles, RTO/NATO, 2011, pp.315-336.

[5] R. Mason, M. Neidbalson, M. Klingenberg, Update on alternatives for cadmium coatings on military electrical connectors, Metal Finishing 108 (2013) 12-20.

DOI: 10.1016/s0026-0576(10)00012-7

[6] J. Zhang, C. Yan, F. Wang, Electrodeposition of Al-Mn alloy on AZ31B magnesium alloy in molten salts, Appl. Surf. Sci. 255 (2009) 4926-4932.

DOI: 10.1016/j.apsusc.2008.12.039

[7] J. Ding, B. Xu, G. Ling, Al-Mn coating electrodeposited from ionic liquid on NdFeB magnet with high hardness and corrosion resistance, Appl. Surf. Sci. 305 (2014) 309-313.

DOI: 10.1016/j.apsusc.2014.03.067

[8] S. Tsipas, J.M. Brossard, M.P. Hierro, J.A. Trillerors, L. Sánchez, F.J. Bolívar, F.J. Pérez, Al-Mn CVD-FBR protective coatings for hot corrosion application, Surf. Coat. Technol. 201 (2007) 4489-4495.

DOI: 10.1016/j.surfcoat.2006.06.023

[9] E.A. Esfahani, H. Salimijazi, M.A. Golozar, J. Mostaghimi, L. Pershin, Study of corrosion behavior of arc sprayed aluminum coating on mild steel, J. Therm. Spray Technol. 21 (2012) 1195-1202.

DOI: 10.1007/s11666-012-9810-x

[10] ISO 9227: 2012, Corrosion tests in artificial atmospheres - Salt spray tests.

[11] ISO 4516: 2002, Metallic and other inorganic coatings - Vickers and Knoop microhardness tests.

DOI: 10.3403/02623390u

[12] T.B. Massalski, 1st ed., Binary alloy phase diagrams. vol. 3", ASM International, Ohio, (1986).