Investigation on metal powder production efficiency of new convergent divergent nozzle in close coupled gas atomisation

In the present study, a new designed close coupled annular slit type nozzle is discussed for the most efficient powder production and the availability of the finest particle size. Pure tin powder was produced by using nitrogen gas at the Dumlupinar gas atomisation unit. It was found that the finest particle size with the highest efficiency was obtained at the atomising pressure where the maximum aspiration pressure is formed. Above a certain gas/melt flow ratio, the resultant particle sizes cannot be considerably reduced by further increasing atomising pressure. At that point, the applied nozzle system reaches a capacity limit, which also marks the point of the most economic work for the production of fine powders with that system. The main achievement of the nozzle discussed in the present study is that the most efficient powder production is accomplished at relatively low atomising gas pressures.