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:
Dec. 31, 1996
Filed:
Dec. 23, 1994
TDK Corporation, Tokyo, JP;
Abstract
Ferrous chloride is used as a starting material and roasted in a steam-containing atmosphere for pyrolysis to prepare a magnetite magnetic powder having a saturation magnetization .sigma.s of 82-92 emu/g and a magnetite phase content of at least 90 wt. %. Prior to roasting, the ferrous chloride may be pre-treated by heat treating it at a low temperature in a non-oxidizing atmosphere, cooling it down to a predetermined temperature, and then exposing it to an oxygen-containing atmosphere. A mixture of ferrous chloride and ferric chloride may also be used as the starting material. These methods can produce magnetite magnetic powder having improved magnetic properties through fewer steps in a simple and easy manner.