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Non-Chromate Conversion Coatings for Magnesium Die Castings
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English
Abstract
Hexavalent chromium-containing baths have traditionally been used as pre-treatments on magnesium alloys. Environmentally friendly alternatives to these baths are being investigated. One alternative seems to be a phosphate-permanganate treatment consisting of a mixture of sodium dihydrogenphosphate and potassium permanganate. The phosphate-permanganate treatment has shown equivalent performance to a standard chrome pickle, both as stand-alone corrosion protection and as a base for subsequent coating. Phosphate-permanganate treatments must be combined with a deoxidizing process to be successful. Another alternative is a fluorozirconate treatment. The paint base properties of fluorozirconate are quite close to what is obtained using a chrome pickle.
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Topic
Citation
Skar, J., Walter, M., and Albright, D., "Non-Chromate Conversion Coatings for Magnesium Die Castings," SAE Technical Paper 970324, 1997, https://doi.org/10.4271/970324.Also In
Characteristics and Applications of Magnesium in Automotive Design
Number: SP-1250; Published: 1997-02-24
Number: SP-1250; Published: 1997-02-24
References
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