ELECTROMAGNETIC ATOMIZATION OF MOLTEN METALS

A new atomization process for molten metal is proposed. The electromagnetic energy induced by direct electric current and stationary magnetic field is utilized in the process instead of kinetic energy as in the fluid impingement and disk rotation which have been used in the conventional metal atomization processes. In order to improve the controllability of this process, splashing phenomena were carefully examined and main obstacles interrupting the continuous operation of the process and obtainment of the sharp particle distribution were searched and removed. A mathematical model was proposed for better understanding of the process. On the basis of the visualization of splashing phenomena and the calculated results of the mathematical model, it was found that the particle size can be mainly controlled by the distance between the nozzle and the electrode, the delay time of the electric current and the mass flow rate of molten metal. The impulse defined as the product of the electric current and the duration of the electric current, and the momentum defined as the product of the mass and the velocity of a splashed particle were calculated from the observed data. From the linear relation found between the impulse and the momentum, the efficiency in which electromagnetic energy was transformed into the kinetic energy for splashing a particle was evaluated.