The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 24, 1989
Filed:
Feb. 02, 1988
Shiang-Jiun Heh, Taipei, TW;
Swe-Kai Chen, Kaohsiung, TW;
Fu-Teh Jin, Kaohsiung, TW;
Li-Kou Chen, Taipei, TW;
Industrial Technology Research Institute, Chutung, TW;
Abstract
A heat-treatment process for producing rare earth-cobalt permanent magnets having relatively high and reproducible magnetic properties wherein one or more controlled cooling rates are applied in temperatures ranging from a sintering temperature and the isothermal annealing temperature. The controlled cooling rates are preferably divided into two steps. In the first step, the cooling rate is preferably greater than 10.degree. C./min. In the second step, the cooling rate is preferably less than 10.degree. C./min. and is ideally in the range of 2.degree.-4.degree. C./min. By the heat-treatment process of this invention, a permanent magnet having a high intrinsic coercivity of more than 20 kOe, a maximum energy product of greater than 19 MGOe, and a coercivity of greater than 8.1 kOe can be reproducibly obtained.