SUPERPARAMAGNETIC OXIDIC PARTICLES, PRODUCTION PROCESS AND USE THEREOF

摘要

PURPOSE: Provided is a process with which a broad range of superparamagnetic particles can be produced from readily available, inexpensive starting materials. CONSTITUTION: Particles are composed of pyrogenic oxide particles which contain superparamagnetic metal-oxide magnetic domains of 3-20 nm in diameters in a nonmagnetic matrix containing a metal oxide or a metalloid oxide and also contain a chloride in amounts of 50-1,000 ppm. The particles are manufactured by a pyrogenic method in which the precursor of the superparamagnetic magnetic domains is mixed with a nonmagnetic metal or the precursor of a nonmetallic matrix in a flame containing air and/or oxygen and the mixture is made to react in the flame. The particles can be used as, for example, a ferromagnetic fluidized material.