Encapsulated nanometer magnetic particles
AssigneeKansas State University Research Foundation
InventorsKenneth J. Klabunde, Dajie Zhang, Christopher Sorensen
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Abstract
Composite nanoparticles comprising an elemental metal core surrounded by a metal-containing shell material are described wherein the particles have an average diameter of from about 5-500 nm; the core metal is preferably selected from the group consisting of the transition metals and especially Fe, Co and Ni, whereas the shell material is advantageously a metal such as an alkaline earth metal, or a metal salt such as a metal oxide or metal halide. The shell material is preferably more oxophilic than the elemental core material, enabling the core metal to remain purely metallic. These core/shell composite particles can be used to fabricate magnetizable recording media such as tapes and disks.
Claims35
A composite comprising a particle having a diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said shell material being selected from the group consisting of In, Nd, and metal salts wherein the metal moiety of such salts is different than said core metal.
A composite comprising a particle having a diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said shell material being selected from the group consisting of metal oxide and metal halide salts.
A composite comprising a particle having a diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said core material being selected from the group consisting of Al, Mg, Co, Ni, Cr, Pd, Au, Cu and Ag, said shell material being selected from the group consisting of the metal sulfide and metal halide salts.
A composite comprising a particle having a diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said shell material being selected from the group consisting of the metal halide salts.
Magnetic recording media comprising a substrate material having a magnetic coating applied to at least one face thereof, said magnetic coating including a synthetic resin binder with magnetizable particles embedded therein, said magnetizable particles comprising composite particles having an average diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said magnetizable particles having two stable opposite magnetic poles switchable under the influence of an externally applied magnetic field.
A composite comprising a particle having a diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said shell material being selected from the group consisting of In, Nd, and metal salts, said composite being formed by co-condensation of vapors of said core elemental metal and said metallic shell material, followed by heating of the condensate.
A magnetic coating adapted for application to a substrate to form magnetic recording media, said coating comprising magnetizable particles dispersed within a synthetic resin binder, said magnetizable particles comprising composite particles having an average diameter of from about 5-500 nm with an elemental metal core surrounded by a metal-containing shell material, said core and shell material being thermodynamically immiscible and each being evaporable at a temperature of up to about 2000.degree. C. under a vacuum, said magnetizable particles having two stable opposite magnetic poles switchable under the influence of an externally applied magnetic field.
Dependencies are inferred from the claim text.