| 简介 |
FIELD : metallurgy.
SUBSTANCE : invention relates to powder metallurgy, particularly to receiving of sintered rare-earth permanent magnets on the basis of R-Fe-B. Sintered rare-earth permanent magnet of compound R1 aR2 bTcAaFeOfMg, where R1 - at least one element, selected from rare-earth elements, including Sc and Y and excluding Tb and Dy, R2 - Tb and/or Dy, T - iron and/or cobalt, A - boron and/or carbon, F - fluorine, O - oxygen, M - at least one element, selected from Al, Cu, Zn, In, Si, P, S, Ti, V, Cr, Mn, Ni, Ga, Ge, Zr, Nb, Mo, Pd, Ag, Cd, Sn, Sb, Hf, Ta and W. Indexes a-g specified atomic percentage of corresponding elements in ally and allows values : 10≤a+b≤15; 3≤d≤15; 0.01 ≤e≤4; 0.04≤f≤4; 0.01≤g≤11; c - the rest. In magnet body F and R2 are distributed so, that its concentration at an everage increases from center to the surface. Grain boundaries envelopes grains of primary phase (R1, R2)2T14A of tetragonal system. Concentration R2/(R1+R2) at grain boundaries is higher than concentration R2/(R1+R2) in grains. Oxy-fluoride (R1, R2) presence at grain boundaries in area of boundaries, stretching from the surface of magnet for depth at least 20 mcm.
EFFECT : sintered magnet allows high coercive force and low remanent magnetization.
5 cl, 2 tbl, 3 dwg, 8 ex |
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