RARE EARTH-IRON-BORON BASED SINTERED MAGNET

• Main Authors: OHASHI TETSUYA, HIROTA KOICHI, NAKAMURA HAJIME, KUME TETSUYA
• Format: Patent
• Language: English; Japanese
• Published: 27.08.2020
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CHEMISTRY; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; INDUCTANCES; MAGNETS; METALLURGY; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

SOLUTION: A R-Fe-B based sintered magnet comprises: a main phase including a HR-rich phase represented by (R',HR)(Fe,(Co))B (where R' represents one or more kinds of elements selected from rare earth elements including Y, and excluding Dy, Tb and Ho, but including Nd as an essential, and HR is an element one or more kinds of elements selected from Dy, Tb and Ho); and a grain boundary phase in the form of one or both of an amorphous phase and a microcrystal phase, provided that the grain boundary phase includes a (R',HR)-Fe(Co)-Mphase having a composition including 25-35 atom% of (R',HR), 2-8 atom% of M(where Mis one or more kinds of elements selected from Si, Al, Mn, Ni, Cu, Zn, Ga, Ge, Pd, Ag, Cd, In, Sn, Sb, Pt, Au, Hg, Pb and Bi), 8 atom% or less of Co, and the balance consisting of Fe. An HR content in the HR-rich phase is higher than an HR content in a center portion of the main phase.EFFECT: The R-Fe-B based sintered magnet of the invention can offer a high coercive force even with small contents of Dy, Tb and Ho.SELECTED DRAWING: Figure 1 【解決手段】（Ｒ'，ＨＲ）2（Ｆｅ，（Ｃｏ））14Ｂ（Ｒ'はＹを含み、Ｄｙ，Ｔｂ及びＨｏを除く希土類元素から選ばれる１種又は２種以上の元素で、Ｎｄを必須とし、ＨＲはＤｙ，Ｔｂ及びＨｏから選ばれる１種以上の元素）で表されるＨＲリッチ相を含む主相と、２５〜３５原子％の（Ｒ'，ＨＲ）、２〜８原子％のＭ1（Ｍ1はＳｉ，Ａｌ，Ｍｎ，Ｎｉ，Ｃｕ，Ｚｎ，Ｇａ，Ｇｅ，Ｐｄ，Ａｇ，Ｃｄ，Ｉｎ，Ｓｎ，Ｓｂ，Ｐｔ，Ａｕ，Ｈｇ，Ｐｂ及びＢｉから選ばれる１種以上の元素）、８原子％以下のＣｏ及び残部のＦｅの組成を有する（Ｒ'，ＨＲ）−Ｆｅ（Ｃｏ）−Ｍ1相を、アモルファス相及び微結晶相の一方又は双方の形態で含む粒界相とを有し、ＨＲリッチ相中のＨＲの含有量が主相の中心部におけるＨＲの含有量より高いＲ−Ｆｅ−Ｂ系焼結磁石。【効果】本発明のＲ−Ｆｅ−Ｂ系焼結磁石は、Ｄｙ，Ｔｂ及びＨｏの含有量が少なくても、高い保磁力を与える。【選択図】図１