| 摘要 |
PURPOSE:To obtain hexagonal ferrite magnetic powder suitable for perpendicular magnetic recording mediums with a large planarity ratio and a sharp distribution of grain size by making a raw composite contain ZrO2 as the vitrification ingredient to form ZrO2-AO. CONSTITUTION:A raw composite contains ZrO2 to form ZrO2-AO as the vitrification ingredient. ZrO2 hardly dissolves in ferrite ingredient and has a high melting point to suppress the crystal growth of hexagonal ferrite in glass, to sharpen the distribution of grain size of magnetic powder, and to tend toward enlargement of planarity ratio. Therefore, a resulting hexagonal ferrite magnetic powder attains a planarity ratio of 3-10 that sufficiently exhibits the effect of perpendicular magnetic recording with the result that the distribution of grain size is sharpened by a grain size of 0.01mum-0.3mum that allows sufficient recording- reproduction at a recording wavelength of 1mum or less. This process can provide a hexagonal ferrite magnetic powder which sharpens the distribution of grain size and exhibits the effect of vertical magnetic recording more sufficiently. |
