Magnetic materials and permanent magnets

A sintered anisotropic permanent magnet having a maximum energy product of at least 10 MGOe and 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 magnet and said permanent magnet has a higher Curie temperature than a corresponding ferromagnetic Fe-B-R base compound containing no Co.

A sintered anisotropic permanent maget having a mean crystal grain size of at least about 1 micron and 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 magnet and at least 50 vol % of the entire magnet is occupied by a ferromagnetic compound of an (Fe,Co)-B-R type tetragonal crystal structure which has a higher Curie temperature than a corresponding ferromagnetic Fe-B-R base compound containing no Co, the magnet having a maximum energy product of at least 10 MGOe.

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, at least one additional element M selected from the group given below in the amounts of no more than the atomic percentages specified below wherein when more than one element comprises M, the sum of M is no more than the maximum value of any one of the values specified below for M actually added and the balance being at least 62 percent Fe, in which Co is substituted for Fe in an amount greater than zero and up to 25 percent of the material and a crystal phase of a ferromagnetic compound having an (Fe,Co)-B-R type tetragonal crystal structure occupies at least 50 vol% of the entire material:

• 3.4% Ti, 6.5% Ni, 5.0% Bi, 6.8% V, 9.6% Nb, 8.3% Ta, 5.4% Cr, 6.1% Mo, 6.0% W, 6.0% Mn, 6.3% Al, 1.3% Sb, 4.2% Ge, 2.0% Sn, 4.2% Zr, and 4.2% Hf;
• and which has a higher Curie Temperature than a corresponding ferromagnetic Fe-B-R-M base composition containing no Co and having said crystal structure.

A sintered anisotropic permanent magnet 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, at least one additional element M selected from the group given below in the amounts of no more than the atomic percentages specified below wherein the sum of M does not exceed the maximum value of any one of the values specified below for M actually added, and the balance being at least 62 percent Fe wherein Co is substituted for Fe in an amount greater than zero and up to 25 percent of the magnet:

• 3.4% Ti, 6.5% Ni, 5.0% Bi, 6.8% V, 9.6% Nb, 8.3% Ta, 5.4% Cr, 6.1% Mo, 6.0% W, 6.0% Mn, 6.3% Al, 1.3% Sb, 4.2% Ge, 2.0% Sn, 4.2% Zr, and 4.2% Hf;
• said permanent magnet having a higher Curie temperature than a corresponding ferromagnetic Fe-B-R-M base composition containing no Co, and having a maximum energy product of at least 10 MGOe.

A sintered anisotropic permanent magnet having a mean crystal grain size of at least about 1 micron and 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, at least one additional element M selected from the group given below in the amounts of no more than the atomic percentages specified below wherein the amount of M is not zero and wherein when more than one element comprises M, the sum of M does not exceed the maximum value of any one of the values specified below for M actually added, 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 magnet:

• 3.4% Ti, 6.5% Ni, 5.0% Bi, 6.8% V, 9.6% Nb, 8.3% Ta, 5.4% Cr, 6.1% Mo, 6.0% W, 6.0% Mn, 6.3% Al, 1.3% Sb, 4.2% Ge, 2.0% Sn, 4.2% Zr, and 4.2% Hf;
• in which a crystal phase of a ferromagnetic compound having an (Fe,Co)-B-R type tetragonal crystal structure occupies at least 50 vol % of the entire magnet and which has a maximum energy product of at least 10 MGOe and a higher Curie temperature than a corresponding ferromagnetic Fe-B-R-M base composition containing no Co.

A magnet as defined in claim 31, wherein said additional element(s) M is contained no more than the amount of atomic percent as specified below:

• 3.5% V, 6.4% Nb, 4.1% Mo, 3.9% W, and 3.8% Al;
• wherein the sum of M does not exceed the maximum value of any one of the values specified above for M actually added.

A powdery magnetic material capable of uniaxial alignment upon orientation in a magnetic field to provide magnetic anisotropy, and having a maximum energy product of at least 10 MGOe and an intrinsic coercivity of at least 1 kOe upon sintering, said material having a mean crystal grain size of at least about 1 micron, and 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 and 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 which has a higher Curie temperature than a corresponding ferromagnetic Fe-B-R base compound containing no Co.