| 摘要 |
PURPOSE:A mixture composed of basic ingredients and substituent ingredients for ferrite and glass-forming substances is melted, then rapidly cooled, thrown into water and heat treated to manufacture fine-particle hexagonal ferrite suitable for high-density vertical magnetization recording. CONSTITUTION:The basic ingredients for hexagonal ferrite, its substituent ingredients for reducing the coersive force and glass-forming substances are thoroughly mixed and the mixture is placed in a platinum vessel with a nozzle on the bottom. After the mixture is melted by heating with a high-frequency heater 2, air or an oxygen gas is sent under pressure through inlet 3 of the platinum vessel 1 to pour the melted mixture on a pair of rollers 4a and 4b, thus effecting rapid cooling. The pan 6 containing water is placed beneath the rollers 4a and 4b so that the amorphous body 5 comes into the water. Thus, amorphous flakes are obtained in well separated from. The flakes are heat treated to give the objective fine-particle hexagonal ferrite. |
