Removal of oxide coating from magnesium powder

Physical and chemical methods were investigated for the preferential removal of corrosion products formed on metallic magnesium powder due to long periods of storage. Chromic acid was found to effectively remove the products of corrosion without affecting the physical characteristics of the powder. The various studies made in detail include the effect of chromic acid concentration, pickling temperature, contact period with the pickle liquor, impurities in the washing medium and temperature of drying the treated powder on the final product. The possibilities of regenerating the spent acid was also examined. (Mr. G. Basak, Senior Scientific Assistant, Messrs V.S. Sampath and P.P. Bhatnagar, Scientists, National Metallurgical Laboratory)