Production of nanocrystalline soft magnetic powders with high Bs by an improved rapid-cooling water-atomization process

A powder of Fe83.3Si4B8P4Cu0.7 composition with D50 of 4.2 μm was prepared by the modified water atomization system named “HPWA/YK”. The obtained powder had a mostly amorphous single phase. The powder was classified to several particle sizes and the difference of enthalpy between the as-quenched state and an after-primary-crystallization state was measured by DSC. As a result, it was found that the HPWA/YK system has better cooling capability than the conventional water atomizing method and the spinning water atomizing method. In conclusion, we consider that the HPWA/YK system contributes to mass production of nanocrystalline soft magnetic powders with high saturation magnetic flux density which require enormously rapid quenching.