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:
Mar. 13, 2012
Filed:
May. 13, 2010
Hiroshi Yamamoto, Suginami-ku, JP;
Tsutomu Katamoto, Ohtake, JP;
Hiroshi Yamamoto, Suginami-ku, JP;
Tsutomu Katamoto, Ohtake, JP;
Toda Kogyo Corporation, Otake-shi, Hiroshima-ken, JP;
Abstract
Spinel-type ferrimagnetic particles having a composition represented by the formula:(MO)·/2(FeO)where M is a divalent metal and n is a molar ratio of Fe to M (n=Fe/M) which is from more than 2.05 to less than 2.5 (2.05<n<2.5). They contain a superparamagnetic component in an amount of not more than 2% by mass, has an average particle diameter of 5 to 30 nm. The particles are respectively coated on surface with a hydroxide of at least one metal Si, Al, P and Zn in an amount of not more than 10% by mass, calculated as the metal. The spinel-type ferrimagnetic particles can exhibit a high coercive force irrespective of fine particles, and are excellent in dispersibility and chemical stability, as well as the magnetic recording medium for high-density recording can exhibit not only excellent frequency characteristics and high output characteristics, but also an excellent weather resistance and a high reliability.