公开(公告)号：DE2743298A1

公开(公告)日：1979-04-05

申请号：DE2743298

申请日：1977-09-27

Applicant: BASF AG

Inventor： JAECKH CHRISTOPHER DIPL CHEM D ,  STECK WERNER DIPL CHEM DR ,  BRODT RUDOLF DIPL CHEM DR ,  OHLINGER MANFRED DIPL CHEM DR ,  LOESER WERNER DIPL ING DR ,  KOESTER EBERHARD DIPL PHYS DR

IPC: B22F1/02 ,  B22F9/22 ,  C22C33/02 ,  H01F1/06 ,  G11B5/62 ,  C21B15/00

Abstract: Acicular ferromagnetic metal particles essentially contain iron and carry, on their surface, from 0.02 to 0.6% by weight of boron in the form of a borate. Such particles may be obtained by reducing an acicular iron oxide with a gaseous reducing agent at from 250 to 500 DEG C, if boron oxyacid or an inorganic salt thereof is deposited on the said iron oxide before reduction. The acicular, ferromagnetic particles are principally used in magnetic recording media and the invention seeks to overcome the difficulty of providing such particles distinguished by a narrow particle size spectrum and pronounced acicular shape.