A single crystal particle powder having a crystal structure of TbCu.sub.7-type of the present invention is represented by the general formula:

[Chemical Formula 1]

(R.sub.1-zM.sub.z)T.sub.x  (1)

or the general formula:

[Chemical Formula 2]

(R.sub.1-zM.sub.z)T.sub.xN.sub.y  (2)

and has a crystal structure of TbCu.sub.7-type,
wherein R is at least one element selected from the group consisting of Sm and Nd, T is at least one element selected from the group consisting of Fe and Co, x is 7.0≤x≤10.0, y is 1.0≤y≤2.0, and z is 0.0≤z≤0.3.

A rare earth sintered magnet is manufactured by preparing a R.sup.1-T-X sintered body having a major phase of R.sup.1.sub.2T.sub.14X composition wherein R.sup.1 is a rare earth element(s) and essentially contains Pr and/or Nd, T is Fe, Co, Al, Ga, and/or Cu, and essentially contains Fe, and X is boron and/or carbon, forming an alloy powder containing 5≤R.sup.2≤60, 5≤M≤70, and 20<B≤70, in at %, wherein R.sup.2 is a rare earth element(s) and essentially contains Dy and/or Tb, M is Fe, Cu, Al, Co, Mn, Ni, Sn, and/or Si, and B is boron, disposing the alloy powder on the sintered body, and heat treating the alloy-covered sintered body.

A rare earth sintered magnet is manufactured by preparing a R.sup.1-T-X sintered body having a major phase of R.sup.1.sub.2T.sub.14X composition wherein R.sup.1 is a rare earth element(s) and essentially contains Pr and/or Nd, T is Fe, Co, Al, Ga, and/or Cu, and essentially contains Fe, and X is boron and/or carbon, forming an alloy powder containing 5≤R.sup.2≤60, 5≤M≤70, and 20<B≤70, in at %, wherein R.sup.2 is a rare earth element(s) and essentially contains Dy and/or Tb, M is Fe, Cu, Al, Co, Mn, Ni, Sn, and/or Si, and B is boron, disposing the alloy powder on the sintered body, and heat treating the alloy-covered sintered body.

A method for producing a silicon based alloy having between 45 and 95% by weight of Si; max 0.05% by weight of C; 0.01-10% by weight of Al; 0.01-0.3% by weight of Ca; max 0.10% by weight of Ti; 0.5-25% by weight of Mn; 0.005-0.07% by weight of P; 0.001-0.005% by weight of S; the balance being Fe and incidental impurities in the ordinary amount.

A method for producing a silicon based alloy having between 45 and 95% by weight of Si; max 0.05% by weight of C; 0.01-10% by weight of Al; 0.01-0.3% by weight of Ca; max 0.10% by weight of Ti; 0.5-25% by weight of Mn; 0.005-0.07% by weight of P; 0.001-0.005% by weight of S; the balance being Fe and incidental impurities in the ordinary amount.

The present invention relates to an RFeB-based magnet in which a treatment (grain boundary diffusion treatment) for diffusing atoms of the heavy rare earth element R.sup.H is performed in a base material including an R.sup.LFeB-based sintered magnet obtained by subjecting crystal grains in a raw-material powder including a powder of an R.sup.LFeB-based alloy containing the light rare earth element R.sup.L, Fe and B to orientation in a magnetic field and then sintering the oriented raw-material powder, or an R.sup.LFeB-based hot-deformed magnet obtained by subjecting the same raw-material powder to hot pressing and then to hot deforming to thereby orient the crystal grains in the raw-material powder, and a method for producing the RFeB-based magnet.

The present invention relates to an RFeB-based magnet in which a treatment (grain boundary diffusion treatment) for diffusing atoms of the heavy rare earth element R.sup.H is performed in a base material including an R.sup.LFeB-based sintered magnet obtained by subjecting crystal grains in a raw-material powder including a powder of an R.sup.LFeB-based alloy containing the light rare earth element R.sup.L, Fe and B to orientation in a magnetic field and then sintering the oriented raw-material powder, or an R.sup.LFeB-based hot-deformed magnet obtained by subjecting the same raw-material powder to hot pressing and then to hot deforming to thereby orient the crystal grains in the raw-material powder, and a method for producing the RFeB-based magnet.

The present disclosure includes a main phase comprising an R.sub.2T.sub.14B compound, and a grain boundary phase. The atom number ratio of B to T in this R—T—B sintered magnet is less than the atom number ratio of B to T in the stoichiometric composition of the R.sub.2T.sub.14B compound, and the relationships 26.0 mass %≤([Nd]+[Pr]+[Ce]+[Dy]+[Tb])−(9×[O]+12×[C])≤27.5 mass %, 0.15 mass %≤[O]≤0.30 mass %, and 0.05 mass %<[Tb]≤0.35 mass % are satisfied, where [Nd] is the Nd content (mass %), [Pr] is the Pr content (mass %), [Ce] is the Ce content (mass %), [Dy] is the Dy content (mass %), [O] is the O content (mass %), and [C] is the C content (mass %). Tb concentration and/or the Dy concentration gradually decreases from the magnet surface toward the magnet interior, at least in part.

This invention relates to magnetocaloric materials comprising alloys useful for magnetic refrigeration applications. In some embodiments, the disclosed alloys may be Cerium, Neodymium, and/or Gadolinium based compositions that are fairly inexpensive, and in some cases exhibit only 2.sup.nd order magnetic phase transitions near their curie temperature, thus there are limited thermal and structural hysteresis losses. This makes these compositions attractive candidates for use in magnetic refrigeration applications. Surprisingly, the performance of the disclosed materials is similar or better to many of the known expensive rare-earth based magnetocaloric materials.

This invention relates to magnetocaloric materials comprising alloys useful for magnetic refrigeration applications. In some embodiments, the disclosed alloys may be Cerium, Neodymium, and/or Gadolinium based compositions that are fairly inexpensive, and in some cases exhibit only 2.sup.nd order magnetic phase transitions near their curie temperature, thus there are limited thermal and structural hysteresis losses. This makes these compositions attractive candidates for use in magnetic refrigeration applications. Surprisingly, the performance of the disclosed materials is similar or better to many of the known expensive rare-earth based magnetocaloric materials.