Plate-like barium ferrite particles suitable for use in magnetic recording and process for producing the same.

摘要

Plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, suitable for use in magnetic recording media, have an average particle diameter of not less than 0.03 µm but less than 0.1 µm, a BET specific surface area of 55 to 90 m2/g, a coercive force of 2.39 x 104 to 11.94 x 104 Am-1 (300 to 1500 Oe) and a magnetization of not less than 57 Am2/kg (57 emu/g) in a magnetic field of 7.96 x 105 Am-1 (10 KOe), and which are represented by the following formula (4):
wherein x and y are independently from 0.02 to 0.12, n is from 4 to 11, the atomic ratio of Co : Fe(III) is from 0.02:1 to 0.13:1 and the molar ratio of Ti : Co is from more than 0 to not more than 0.8:1.