PURPOSE: To prevent not only the oxidation of a magnet alloy powder but also the deterioration of magnetic characteristics in a manufacturing process by using an org. solvent of a specific composition in a process for pulverizing a raw material alloy according to a wet system.
CONSTITUTION: As a solvent for the wet pulverization of a rare earth element permanent magnet alloy, an aliphatic hydrocarbon type and/or aromatic hydrocarbon type org. solvent having a b.p. of 200°C or lower, pref., 150°C or lower such as n-hexane or n-heptane is used. Further, the amount of dissolved oxygen in said org. solvent is set to 0.05wt.% or less and the amount of dissolved moisture therein is set to 0.05wt.% or less. At the time of pulverization, the surface area of a powder increases with the advance of pulverization and the active oxidation of a newly formed surface is generated but, when this org. solvent is used, the oxidation of the magnet alloy powder is prevented and the deterioration of magnetic characteristics in the manufacturing process can be prevented.
OHASHI TAKESHI
HIROSE NAOYUKI
