| 摘要 |
PROBLEM TO BE SOLVED: To provide a material for permanent magnets, which has good moldability and good magnetic properties. SOLUTION: Goethite (FeOOH) is mixed with aqueous cobalt salt, aqueous nickel salt and aqueous neodymium so that the salts may be adsorbed on needlelike crystals of goethite. After neutralized and washed with water, the geothite crystals are baked in an air or oxygen-rich atmosphere, and then reduced by mixing with powder of neodymium and boron in a hydrogen atmosphere. The crystals are heated to 500-1100 deg.C in a hydrogen or nitrogen atmosphere until they are shaped like needles with an aspect ratio of less than 3:1, or like dice or spheres. |
