Hexagonal plate-like barium ferrite particles and a method for manufacturing the magnetic recording

摘要

PURPOSE:To further increase the magnetization value of the titled powder in the magnetic field of 10kOe by a method wherein a specific hexagonal plate type BaFe12-2xMxTixO19 (0.6=X=1.2, M is the dihydric metal ion of Co(II) or Co (II) and other than Co) fine grain is used. CONSTITUTION:A hexagonal plate type BaFe12-2xMxTixO19[0.6=X=1.2, M is dihydric metal ion of Co (II) or Co (II) and other than Co] fine grains, having the width of 0.1-0.4mum, a BET ratio surface area value of 20-50m2g-1, the magnetization (M) value of 40emug-1 or above under the magnetic field of 10kOe and the coersive force (Hc) value of 500-1,000Oe, is used. Also by performing a hydro-heat treatment at the temperature of 250-330 deg.C using strong alkaline suspension solution containing at least Co (II) as Ti (IV), Ba (II) and dihydric metal ions M (II), a hexagonal plate type BaFe12-2xMxTixO19 (0.6=X =1.2) fine grains having the width of 0.05-0.4mum can be formed from the aqueous solution, and after said fine grains have been treated using a solution containing Si (IV), they are heat-treated at 900 deg.C or below, and the above-mentioned hexagonal plate type BaFe12-2xMxTixO19 fine grains can be obtained.