| 摘要 |
PROBLEM TO BE SOLVED: To considerably shorten the time required to pulverize calcined powder by adding a specified amt. of a water-soluble carbonate and/or a COOH-contg. salt to a mixture of the calcined powder with a solvent and carrying out wet pulverization when the mixture is wet-pulverized, molded and sintered to obtain a ferrite magnet. SOLUTION: A water-soluble carbonate such as sodium carbonate and/or a COOH-contg. salt such as ammonium polycarboxylate is added by <=1 wt.%, preferably 0.4-0.8 wt.% to a mixture of stock powder such as calcined powder obtd. by calcining an SrCO3 -Fe2 O3 mixture with a solvent such as water, and wet pulverization is carried out. The powder-solvent mixture may be wet- pulverized in gaseous CO2 or gas contg. gaseous CO2 . The time required to pulverize the powder can be shortened by 30-50% as compared with the conventional method and the objective low-cost ferrite magnets having high performance are stably mass-produced. |
