| 摘要 |
PURPOSE:To inexpensively obtain anisotropy acicular magnetic powder showing ferromagnetism by specifying the compsn. consisting of rare earth elements, Fe and N and specifying the shape dimension of powdery grains. CONSTITUTION:A circular iron powder having the shape that the length of an acicular grain is regulated to 0.05 to 10mum and the width to <=2.0mum, rare earth oxide powder and a reducing agent such as Ca are mixed in a specific ratio. Next, this mixture is heated to about 600 to 1200 deg.C in a inert gas atmosphere to alloy rare earths and iron. The obtd. alloy is continuously heated to about 250 to 800 deg.C in an gaseous atmosphere of N2 gas or compounds contg. nitrogen such as NH3 and is nitrided. After that, the compound as a reducing agent is dissolved away by water or weak acid from the obtd. rare earth-iron nitride. Thus, the longitudinal anisotropy acicular magnetic powder expressed by the formula REXFe100-X-YNY (RE denotes rare earth elements and, by atom, 3<=X<=30% and 0.01<=Y<=25% are satisfied) and whose grain length is regulated to 0.05 to 10mum and the width to <=2.0mum can be obtd. |
