MANUFACTURING METHOD OF MAGNET ALLOY POWDER WITH COATING

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PROBLEM TO BE SOLVED : To provide a method of forming a coating including a chrome oxide to a front surface of an iron system magnet alloy powder containing a rare earth element. SOLUTION : A manufacturing method of a magnet alloy powder with a coating, includes : a solution preparation step of preparing a chrome solution by adjusting a pH to -1.0 or more and 7.0 or less, and hexavalent chromium ion concentration with conversion of an oxidation chrome (VI) to 0.1 g/L or more and 50 g/L or less by adding hexavalent chromium ion and inorganic acid into an organic solvent in which a water content amount is 0 volume% or more and 25 volume% or less; an aging step of performing a period aging of the chrome solution for 5 days or more and 45 days or less under 0-degree or more and 40-degree or less; and an immersion step of immersing an iron system magnet alloy powder containing a rare earth element into the chrome solution, and forming a coating containing the oxide chrome onto the front surface of the iron system magnet alloy powder. SELECTED DRAWING : Figure 1 COPYRIGHT : (C)2019, JPO&INPIT