Coatings magnesium alloys

Narayanan, T.S.N.S., Park, I.S., and Lee, M.H. (2014) Strategies to improve the corrosion resistance of microarc oxidation (MAO) coated magnesium alloys for degradable implants. Prog. Mater. Sci., 60, 1-71. 

Song G-L. (2008a), An electroless e-coating bath sealing technique for anodized and conversion coated magnesium alloys , MPL-641(GM confidential report). 

Tsubakino H, Yamamoto A, Sugahara K, Fukumoto S, (2003), Corrosion resistance in magnesium alloys and deposition coated magnesium alloy , Materials Science Forum, 419-422, 915-920. 

Bartak, D E, Lemieux, B E Woolsey, E R (1993), Two-step chemical/electrocherrdcal process for coating magnesium alloys. US Patent 5240589. 

Nykyforchyn, H M, Dietzel, W, Klapkiv, M D Blawert, C (2003), Corrosion properties of Conversion Plasma Coated Magnesium Alloys. In Kainer, K U (ed.) Magnesium, 6th International Conference Magnesium Alloys ami their Applications. Wolfsburg (D). 

Magnesium anodes usually consist of alloys with additions of Al, Zn and Mn. The content of Ni, Fe and Cu must be kept very low because they favor selfcorrosion. Ni contents of >0.001% impair properties and should not be exceeded. The influence of Cu is not clear. Cu certainly increases self-corrosion but amounts up to 0.05% are not detrimental if the Mn content is over 0.3%. Amounts of Fe up to about 0.01% do not influence self-corrosion if the Mn content is above 0.3%. With additions of Mn, Fe is precipitated from the melt which on solidification is rendered harmless by the formation of Fe crystals with a coating of manganese. The addition of zinc renders the corrosive attack uniform. In addition, the sensitivity to other impurities is depressed. The most important magnesium alloy for galvanic anodes is AZ63, which corresponds to the claims in Ref. 22. Alloys AZ31 and M2 are still used. The most important properties of these alloys are... 

King, J. F., Adamson, K. G. and Unsworth, W., Impregnation of Anodic Films for the Protection of Magnesium Alloys, Ministry of Defence D.Mat. Report No. 193, February (1973) Adamson, K. G., King, J. F. and Unsworth, W., Evaluation of High Temperature Resistant Coatings for the Protection of Magnesium Alloys, Ministry of Detence D.Mat. Report No. 196, July (1973)... 

Other investigations indicate that half-tide conditions give results similar to fully immersed conditions, and that in sea-water the 99-5% aluminium coating is preferred to aluminium-zinc or aluminium-magnesium alloy coatings. 

Etch priming is widely used on aluminium alloy, and is particularly effective on cadmium and zinc. The adhesion to stainless steel and titanium is good. It has also been used quite widely on bare steel and on magnesium alloy, but on these metals its performance is not, in the opinion of some investigators, always quite reliable. For best protection the etch primer coating is followed with a full paint scheme. 

A. N. Khramov, V. N. Balbyshev, L. S. Kasten and R. A. Mantz, Sol-gel coatings with phosphonate functionalities for surface modification of magnesium alloys, Thin Solid Films, 2006, 514, 174. 

Acrylic resins - [MAGNESIUMAND MAGNESIUM ALLOYS] (Vol 15) - [COATING PROCESSES - POWDER TECHNOLOGY] (Vol 6) -photocuring [RADIATION CURING] (Vol 20) -plasticization of [PLASTICIZERS] (Vol 19) -thiols m [THIOLS] (Vol 24)... 

Post-Treatments. Although many post-treatments have been used over plated metals, chromate conversion coatings remain as the most popular. Chromates are used to improve corrosion resistance, provide good paint and adhesive base properties, or to produce brighter or colored finishes. Formulations are usually proprietary, and variations are marketed for use on zinc, zinc alloys, cadmium, copper and copper alloys, and silver (157). Chromates are also used on aluminum and magnesium alloys (158,159). More recently, chromate passivation has been used to extend salt spray resistance of autocatalytic nickel plated parts. 

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