Patent ID: 11600413

Abstract:
R—Fe—B sintered magnet has a main phase containing R2(Fe,(Co))14B intermetallic compound and a grain boundary phase. The inter-particle grain boundary includes an expanded width part that is surrounded by a narrow width part at which the inter-particle width is 10 nm or less and that has a structure distended in the inter-particle width direction as compared with the grain boundary width of the narrow width part; the inter-particle width at the expanded width part is at least 30 nm; Fe/R ratio in the expanded width part is 0.01-2.5; the main phase includes, in the surface part thereof, an HR-rich phase represented by (R′,HR)2(Fe,(Co))14B (R′ represents rare-earth elements excluding Dy, Tb, and Ho, and that essentially include Nd; and HR represents Dy, Tb, and Ho); the contained amount of HR in the HR-rich phase is higher than that in the central part of the main phase.