Atomization of Liquid Metals Using Twin Roller Technique

A description is given of a novel process for producing metal powders which has a significantly lower energy requirement than conventional atomization processes and is also capable of high throughputs. Atomization is achieved by feeding a stream of molten metal between rapidly rotating rollers (up to 150 rps). Typically the roller gap is 50–150 μm. In order to effect atomization it is essential that the metal feed remains in the liquid state while in contact with the roller surface so that subsequent disintegration can occur. To this end, various roller materials and coatings have been investigated. Despite certain roller coating limitations, it is possible to atomize a wide range of metals including iron-base alloys, copper, and low melting point metals. Experimental results suggest that powder with a mean diameter of 100 μm might be produced by this method. An outline is given of a mathematical model which describes the mechanism of disintegration. The validity of the model and its implications are also discussed.