Process for producing magnetic iron oxide particles for magnetic recording
AssigneeIshihara Sangyo Kaisha, Ltd.
InventorsArata Koyama, Makoto Ogasawara, Shigeru Takatori
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Abstract
A process for producing magnetic ion oxide particles for magnetic rcording which comprises heat-treating a magnetic iron oxide particles of magnetite, berthollide or maghemite as a starting materials, in the presence of a zinc component or both a zinc component and a silicon component at a temperature of 400.degree. to 700.degree. C. in a specific atmosphere, and if necessary, subjecting the heat-treated particles to wet treatment and/or dry treatment, thereby doping the particles with zinc ions resulting in magnetic iron oxide particles having an improved saturation magnetization, a proportion of said zinc ions being 2 to 9 at. % by weight relative to the total amount of iron ions.
Claims24
A process for producing magnetic iron oxide particles for magnetic recording, which comprise heat-treating magnetic iron oxide particles as a starting material, in the presence of a zinc component or both a zinc component and a silicon component at a temperature of 400.degree. to 700.degree. C. in a non-reducing atmosphere, thereby doping said particles with zinc ions resulting in magnetic iron oxide particles having an improved saturation magnetization, a proportion of said zinc improved saturation magnetization, a proportion of said zinc ions being 2 to 9 at. % by weight relative to the total amount of iron ions.
A process for producing magnetic iron oxide particles for magnetic recording comprising the steps of heat-treating a starting material, magnetic iron oxide particles, in the presence of a zinc component or both a zinc component and a silicon component at a temperature of 400.degree. to 700.degree. C. in a non-reducing atmosphere and then immersing said particles in an acidic solution or an alkaline solution, thereby doping said particles with zinc ions resulting in magnetic iron oxide particles having an improved saturation magnetization, a proportion of said zinc ions being 2 to 9 at. % by weight relative to the total amount of iron ions.
A process for producing magnetic ion oxide particles for magnetic recording comprising the steps of heat-treating a starting material, magnetite particles, in the presence of a zinc component or both a zinc component and a silicon component at a temperature of 450.degree. to 700.degree. C. in an inert atmosphere and then treating by wet oxidation and/or dry oxidation, thereby doping said particles with zinc ions resulting in berthollide particles having an improved saturation magnetization, a proportion of said zinc ions being 2 to 9 at. % by weight relative to the total amount of iron ions.
A process for producing magnetic iron oxide particles for magnetic recording comprising the steps of heat-treating a starting material, magnetite particles, in the presence of a zinc component or both a zinc component and a silicon component at a temperature of 450.degree. to 700.degree. C. in an inert atmosphere, then treating by wet oxidation and or dry oxidation and, thereafter, immersing said particles in an acidic solution or an alkaline solution, thereby doping said particles with zinc ions resulting in berthollide particles having an improved saturation magnetization, a proportion of said zinc ions being 2 to 9 at. % by weight relative to the total amount of iron ions.
Dependencies are inferred from the claim text.