Efficient laser methods for producing spherical powders

Abstract

A new process of laser gas atomization has been developed to obtain a spherical metal powder with a particle size of 30-100 μm using laser beams of conical geometry. A process for obtaining a spherical powder in a wide size range of 50 nm - 100 μm, in which a continuous near-surface optical discharge with a temperature of 20 kK is formed using conical laser beams in an inert gas flow, into which the material is introduced in the form of a wire or a powder flow has been designed. Particle condensation is strongly and rapidly quenched by the inert gas flow, resulting in high supersaturation. The efficiency of the proposed laser methods for producing powders is up to 0.5 kg/kWh at an electric power of 16 kW, while the existing, most efficient methods of plasma and gas spraying provide an efficiency of no better than 0.1-0.25 kg/h kW. The method can be used to obtain powders from various materials - metals, ceramics, plastics, suspensions. The new process of laser centrifugal atomization has been elaborated. Melting or evaporation of the end of a rotating hollow cylinder by a laser system ensures a highly efficient process for obtaining spherical powder in the nano and micro size range