Magnetic materials and permanent magnets

  • US 4,792,368 A
  • Filed: 07/25/1983
  • Issued: 12/20/1988
  • Est. Priority Date: 08/21/1982
  • Status: Expired due to Term
First Claim
Patent Images

1. An anisotropic magnetic material having a mean crystal grain size of at least about 1 micron and an intrinsic coercivity of at least 1 kOe, and having a maximum energy product of at least 10 MGOe upon sintering, said material consisting essentially of, by atomic percent, 12-20 percent R wherein R is at least one element selected from the group consisting of Nd, Pr, La, Ce, Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu and Y and wherein at least 50% of R consists of Nd and/or Pr, 5-18 percent B, and the balance being at least 62 percent Fe, in which Co is substituted for Fe in an amount greater than zero and not exceeding 25 percent of the material, at least 50 vol % of the entire material is occupied by a ferromagnetic compound having an (Fe,Co)-B-R type tetragonal crystal structure and a higher Curie temperature than a corresponding ferromagnetic Fe-B-R base compound containing no Co.

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