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US 8,361,242 B2Granted
Powders for rare earth magnets, rare earth magnets and methods for manufacturing the same
AssigneeVacuumschmeize GmbH & Co. KG
InventorsRolf Blank, Matthias Katter, Werner Rodewald, Boris Wall
Life of this patent
Estimating the term…
Abstract
A powder consists essentially by weight, of 28.00≦R≦32.00%, where R is at least one rare earth element including Y and the sum of Dy+Tb>0.5, 0.50≦B≦2.00%, 0.50≦Co≦3.50%, 0.050≦M≦0.5%, where M is one or more of the elements Ga, Cu and Al, 0.25 wt %<O≦0.5%, 0.15% or less of C, balance Fe.
Claims30
A method to produce powders for use in R—Fe—B—M type permanent magnets comprising:
- melting an alloy consisting of, by weight, 28.00≦R≦32.00%, where R is at least one rare earth element including Y and the sum of Dy+Tb>0.5, 0.50≦B≦2.00%, 0.50≦Co≦3.50%, 0.050≦M≦0.5%, where M is one or more of the elements Ga, Cu and Al, 0.25 wt %<O≦0.5%, 0.15% or less of C, 0.15% or less of N, balance Fe;
- casting said alloy to form at least one ingot, wherein the solidified ingot comprises finely dispersed α-Fe phase, and R2Fe14B and R-rich constituents;
- annealing said ingot at a temperature in the range of 800° C. to 1200° C. under an inert atmosphere of Ar or under vacuum to form an ingot which is free of said α-Fe phase;
- hydrogenating said ingots in hydrogen gas in order to hydrogenate the R-rich constituents;
- coarsely pulverising said ingot to form a coarsely pulverised powder;
- performing a fine pulverisation of said coarsely pulverised powder in an atmosphere comprising oxygen, thereby forming an oxidized, finely pulverised powder;
- wherein said finely pulverised powder comprises an oxygen content of 0.25 wt %<O≦0.5 wt %.
4 more elements
A method of producing a powder for use in the manufacture of R—Fe—B-M type permanent magnets, comprising:
- providing an alloy consisting of, by weight, 28.00≦R≦32.00%, where R is at least one rare earth element including Y and the sum of Dy+Tb>0.5, 0.50≦B≦2.00%, 0.50≦Co≦3.50%, 0.050≦M≦0.5%, where M is one or more of the elements Ga, Cu and Al, 0.25 wt %<O≦0.5%, 0.15% or less of C, 0.15% or less of N, balance Fe, said alloy having the form of an ingot which comprises finely dispersed α-Fe phase, and R2Fe14B and R-rich constituents;
- annealing said ingot at a temperature in the range of 800° C. to 1200° C. under an inert atmosphere of Ar or under vacuum to form an ingot which is free of said α-Fe phase;
- hydrogenating said ingots in hydrogen gas in order to hydrogenate the R-rich constituents;
- coarsely pulverising said ingot to form a coarsely pulverised powder;
- performing a fine pulverisation of said coarsely pulverised powder in an atmosphere comprising oxygen, thereby forming an oxidized, finely pulverised powder;
- wherein said finely pulverised powder comprises an oxygen content of 0.25 wt %<O≦0.5 wt %.
3 more elements
Dependencies are inferred from the claim text.