Production of rapidly solidified metal powders by water cooled rotating disc atomisation

Abstract

In this study production of rapidly solidified metal powders by water cooled rotating disc has been investigated. A rotating disc was cooled by water which was not in contact with the molten metal and the produced powders during atomisation. This method is an effective process to produce rapidly solidified powders and ribbons.Tin, lead, aluminium, zinc, and AA 2014 aluminium alloy powders and ribbons were produced using different types of discs. Parameters such as disc rotation velocity, disc shape, diameter of liquid metal stream, and superheat were investigated. The results showed that increasing disc rotation velocity, decreasing liquid metal stream diameter, and increasing superheat resulted in finer particles as expected.Different types of discs such as flat, flat with fins, and cone with fins were used to investigate the effects of the disc geometry. Performance of the flat type disc with rectangular fins was better than that of the others.Metallographic examinations showed that estimated cooling rates of atomised AA 2014 powders were between 104–105 K s-1 depending on particle size. With the ribbons cooling rates were relatively higher, of the order of 105–106 K s-1.