PURPOSE: To prevent irreguarity and deterioration of magnetic characteristics, by super-quenching molten alloy of rare earth based permanent magnet material composition in a super-quenching atmosphere gas composed of helium gas and/or hydrogen gas.
CONSTITUTION: Single gas or mixed gas selected out of helium gas and hydrogen gas is used as super-quenching atmosphere gas when molten alloy of rare earth based permanent magnet material composition is super-quenched. In another case, mixed gas wherein argon gas of about 30vol% or less is added to the single gas or the mixed gas is used. The rare earth based permanent magnet material has the copmostion expressed by a formula where R is one or more kinds of rare earth elements, M is one or more kinds of Fe, Co, Ni and Mn, A is one or more kinds of Ti, Zr, Hf, etc., X is one or more hinds of B, C, Si and P, 0.60≤α≤0.85, 0≤β≤0.10 and γ<0.15. Thereby magnetic characteristic are stabilized, and excellent rare earth based permanent magnet material is obtained.
KOYAMA KEIJI
FURUYA TAKASHI
