Patent ID: 7608158

Claim:
A method of maintaining magnetic nanoparticle size comprising: providing two or more magnetic nanoparticles in a nanoscale dispersion, wherein each nanoparticle contains at least one metal, an initial nanoparticle size and shape, and does not interact with a pulverized salt at a treatment temperature; wherein the two or more magnetic nanoparticles are selected from the group consisting of iron-platinum, cobalt-platinum, samarium-cobalt, ceramic material, intermetallic particles, iron-cobalt, and neodymium-iron-boron; mixing the two or more magnetic nanoparticles with the pulverized salt that includes a melting point higher than 500 degrees Centigrade in the nanoscale dispersion; treating the nanoscale dispersion with heat at the treatment temperature that is at least about 500 degrees Centigrade; and isolating the two or more nanoparticles from the nanoscale dispersion, wherein the isolated two or more magnetic nanoparticles have not agglomerated and have an annealed size and shape substantially the same as the initial nanoparticle size and shape.