An atomiser is designed for the production of nanostructured, submicronic metal powders with melting points up to 2000°C. The alloy is induction-melted in a vacuum and subsequently argon-stirred for homogenisation. The break-up of the superheated melt into spherical droplets is carried out in a tubular ultrasonic resonator under argon or helium atmosphere. Droplet size is governed by the ultrasonic parameters of newly developed transducers. Rapid solidification of the atomised melt is the result of convective cooling. For the controlled passivation of the solidified droplets, a mixture of oxygen and carbon dioxide is added to the gas flowing inside the atomising vessel. Once optimised, this method is expected to be commercially viable for the production of special powders in small batches for advanced powder technology processing.
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