| 摘要 |
<p>A composition of a crystalline ferromagnetic material based upon nanoscale cobalt carbide particles and to a method of manufacturing the ferromagnetic material of the invention via a polyol reaction are disclosed. The crystalline ferromagnetic cobalt carbide nanoparticles of the invention are useful for high performance permanent magnet applications. The processes according to the invention are extendable to other carbide phases, for example to Fe-, FeCo-carbides. Fe- and FeCo-carbides are realizable by using as precursor salts Fe-, Co-, and mixtures of Fe- and Co-salts, such as acetates, nitrates, chlorides, bromides, citrates, and sulfates, among others. The materials according to the invention include mixtures and/or admixtures of cobalt carbides, as both Co2C and Co3C phases. Mixtures may take the form of a collection of independent particles of Co2C and Co3C or as a collection of particles which consist of an intimate combination of Co2C and Co3C phases within individual particles. The relative proportions of these two phases as well as the morphology of each phase contribute to their attractive permanent magnet properties, particularly at low temperatures through room temperature and up to over 400 K.</p> |
