| 摘要 |
PURPOSE:To produce a magnetic powder capable of forming an easily magnetizable axis in the coated film thickness direction only by coating, by coprecipitating hydroxides of iron and barium under specific conditions, and treating the resultant coprecipitates at a high temperature under a high pressure. CONSTITUTION:(i) An aqueous solution containing an iron salt, e.g. Fe(NO3)3. 9H2O and a barium salt, e.g. Ba(NO3)2 at 7.5-9.5 ratio between the iron ions and the barium ions is mixed with an aqueous solution of sodium hydroxide (at 1.1-3 ratio between the total nonmetallic ions in the iron and barium salts and the hydroxyl ions). (ii) The resultant suspension is then placed in an autoclave, kept at a temperature (T) expressed by the formula for >=1hr and naturally cooled to collect a solid material, which is then washed with water and dried to afford the aimed magnetic powder. |
