| 摘要 |
PROBLEM TO BE SOLVED: To suppress the dispersion in characteristics of an electronic part for stabilizing the quality thereof, by a method wherein, after rapid refrigeration of a mixed slurry comprising multiple metallic oxides containing pure water, the mixed slurry is heated in vacuum, the dried up powder is calcinated and granulated after crushing. SOLUTION: Cobalt oxide, manganese oxide, iron oxide are blended with one another in a pure water containing ball mill in the first step, then the blended slurry are contained in a highly pure and precise alumina container 5 to be held in a refrigerator while being ultrasonically oscillated, and then rapidly refrigerated after stopping the ultrasonic oscillation so as to manufacture a refrigerated body 4 in the second step. The refrigerated body 4 is pressure- reduced in a drier 7 to be dehydration dried up at the temperature e.g. less than 100 deg.C in the third step. The blended powder after drying up is calcinated for two hours e.g. at the temperature of 900 deg.C in the state of being held in the alumina container 5 in the fourth step. Finally, the calcinated material is clushed by the ball mill to be granulated and dried up in the fifth step. |
