| 摘要 |
PURPOSE:To provide the powder being facile in particle size adjustment, free from sintering and getting out of shape during the treatment and compact, and having excellent magnetic characteristics, by having a specific compound and a hydroxide contained in the suspension of ferrous hydroxide when forming alpha-oxy ferric hydroxide in an alkali region. CONSTITUTION:An oxygen containing gas is introduced into the suspension of ferrous hydroxide having an adjusted pH of at least 11 to form alpha-oxy ferric hydroxide. One compound of Zn and Al compounds and the hydroxide of an alkaliearth metal (expressed by Me) are contained in the above-mentioned suspension prior to the gas introduction. The particle size of the magnetic powder being mainly the formed alpha-oxy ferric hydroxide or the metallic iron finally obtained can be adjusted by adjusting the amount of Zn or Al compound. The sintering and getting out of shape in the particles during the heat treatment can be also very effectively inhibited, and the alkaline region reaction results in the retained compactness of the powder. |
