Patents by Inventor Takashi Hashikawa

Takashi Hashikawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Methods for manufacturing R-Fe-B type magnet raw material powder and R-Fe-B type magnet
    Patent number: 6149861
    Abstract: It is an object of the present invention to provide a method for manufacturing a raw material alloy powder that can be utilized effectively in the regeneration of surplus or defective R--Fe--B type sintered magnets while leaving the main phase crystal grains alone, and a method for manufacturing an R--Fe--B type magnet. Surplus or defective R--Fe--B type sintered magnets are pulverized, acid washed, and dried, after which this product is subjected to a calcium reduction treatment and washed to remove the calcium component, which allows a raw material alloy powder composed of an Nd.sub.2 Fe.sub.14 B main phase system, which contributes the most to magnet characteristics, to be regenerated efficiently. An alloy powder for compositional adjustment that improves sintering and adjusts the composition is added to this main phase system raw material alloy powder to produce a sintered magnet, which facilitates the manufacture of a sintered magnet with superior magnet characteristics.
    Type: Grant
    Filed: April 6, 2000
    Date of Patent: November 21, 2000
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Yuji Kaneko, Yasuhide Sasakawa, Katsuya Kase, Takashi Hashikawa, Kaname Takeya