Rare earth magnet and motor
A rare earth magnet capable of reducing an eddy current loss by virtue of a low-cost, simple configuration, when mounted in a motor, is to be provided. The rare earth magnet can include a magnet body that includes a rare earth element and iron; and a resistive layer formed on at least one surface of the magnet body, the resistive layer comprising a rare earth element, iron, and oxygen and having an average volume resistivity of 10 3 Ωcm or more and a thickness of from 3 to 25 μm.
1. A rare earth magnet comprising:
a magnet body comprising a rare earth element and iron; and
a resistive layer formed on at least one surface of the magnet body,
wherein the resistive layer comprises a rare earth element, iron, and oxygen,
wherein the resistive layer has an average volume resistivity of 10 3 Ωcm or more and a thickness of from 3 to 25 μm to reduce eddy current loss,
wherein the resistive layer does not include fluorine atoms, and
wherein the resistive layer comprises:
a first layer covering the magnet body and comprising at least, a rare earth element, iron, and oxygen;
a second layer covering the first layer and comprising at least, a rare earth element, iron, and oxygen; and
a third layer covering the second layer and comprising at least, iron and oxygen,
wherein the second layer, including a 2-A layer and a 2-B layer, has a less content of iron than each of the first and the third layers and has a structure such that 2-A layer and 2-B layer are alternately laminated, the 2-B layer having a more content of iron and a less content of R than the 2-A layer, wherein R is the rare earth element.
2. The rare earth magnet according to claim 1 , wherein the magnet body comprises Nd, Pr, Dy, or Tb.
3. The rare earth magnet according to claim 1 , comprising a heavy rare earth element(s) and having a region where a concentration of the at least one heavy rare earth element decreases from the at least one surface of the rare earth magnet toward an inside thereof.
4. A motor comprising a plurality of the rare earth magnets according to claim 1 , wherein each of the rare earth magnets is in contact with an adjoining rare earth magnet through the resistive layer.
5. A motor comprising a plurality of the rare earth magnets according to claim 1 , wherein the rare earth magnet is in contact with a rotor core through the resistive layer.