Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyota Jidosha Kabushiki Kaisha

Yukio Takada

Yuji Kaneko

Motoki Hiraoka

Keiu Kanada

Hisaaki Takao

A rare earth magnet production method of the present invention includes a placing step of placing a magnet material including a compact or a sintered body of powder particles having a rare earth magnet alloy, and a diffusing material containing a diffusing element to improve coercivity, in a vicinity of each other; and a diffusing step of diffusing the diffusing element into an inside of the magnet material by exposing the magnet material heated to vapor of the diffusing element evaporated from the diffusing material heated; and wherein the diffusing step is a step of heating the diffusing material independently of the magnet material to diffusing material temperature which is different from heating temperature of the magnet material called magnet material temperature.

Rare earth magnet and method for producing the same

A method for producing a rare earth magnet material which allows efficient Dy or the like diffusion into an inside thereof. This method includes a preparation step of preparing a powder mixture of magnet powder including one or more rare earth elements including neodymium, boron, and the remainder being iron; and neodymium fluoride powder; a heating step of heating a compact of the powder mixture and causing oxygen around magnet powder particles to react with the fluoride powder, thereby obtaining a lump rare earth magnet material in which neodymium oxyfluoride is wholly distributed. The fluoride powder traps oxygen enclosed in the powder mixture and fixes the oxygen as stable NdOF. When Dy is diffused into this rare earth magnet material, Dy smoothly enters into its inside without being oxidized at grain boundaries. Consequently, coercivity of the entire rare earth magnet material can be efficiently increased without wasting scarce Dy.

Rare earth magnet material and method for producing the same

A process for producing a rare earth magnet comprises: an adhesion step of causing a diffusion element capable of diffusing inwardly to adhere to the surface part of a magnet material comprising a compact or sintered body of rare earth alloy particles; and an evaporation step of heating the magnet material in vacuum to evaporate at least a portion of the diffusion element having been retained on or in the surface part of the magnet material.

Growing community of inventors

Nisshin, Japan

Yukio Takada