| 摘要 |
PURPOSE:To provide magnetic powder for high-density recording wherein the coercive force is 200-2000 oersteds enabling recording and reproducing with a normal magnetic head and the mean diameter of the powder is 0.01-0.3mum which has good short wavelength characteristics by substituting the Fe atom in ferrite with the other specific atom. CONSTITUTION:Magneto plumbite type (one or more of Ba, Sr, Pb, Ca) ferrite is selected for magnetic powder and part of the Fe<3+> ion in the ferrite is substituted with a Co<2+>-Nb<5+> ion or a Co<2+>-Sb<5+> ion for controlling coercive force. A B2O3-AO group is selected for a glass forming material and substituting type ferrite of general formula: ABaFe12-3/2xCoxM1/2xO19, x = 0.5-1.1 is sufficiently mixed. The mixture is prepared in a platinum container 1, heated by a high frequency heater 2, the gas exposed to air pressure 3, and poured between rollers 4a and 4b to obtain powder for a ribbon 5. The M in the formula is one of V, Nb, Sb or Ta. |
