Metal powder for dust core application was developed. The powder can be produced improved high-pressure water atomization process. The process has produced powder of spherical shape and lower coercivity. The dust core obta ined shows lower core loss.

In order to obtain spherical fine powder, we have developed a new method of high-pressure water atomization system using swirl water jet with the swirl angle . The effect of nozzle apex angle upon the morphology of atomized powders was investigated. Molten copper was atomized by this method, with rad (swirl water jet) and rad (conical water jet). It was found that the median diameter of atomized powders decreased with decreasing down to 0.35 rad in each , but under θ<0.35 rad, increased abruptly with decreasing for rad, while it was still decreased with decreasing for rad.

To improve the properties of fine metal powder, such as particle size distribution and geometric standard deviation, this work was done at various atomizing conditions. The new atomization mechanism and the correlation equation were proposed to estimate the mean particle diameter.