| 摘要 |
PURPOSE:To obtain a pore-free plate magnetite particle powder having average diameter and specific surface area being in the prescribed range, free from sintering and having excellent dispersibility in a resin, by subjecting an alkaline suspension containing water-containing iron(III)oxide particle and iron(II) hydroxide to hydrothermal treatment in the presence of sulfuric acid radical at a specific temperature. CONSTITUTION:An alkaline suspension containing water-containing iron(III)oxide and iron(II)hydroxide is subjected to hydrothermal treatment in the presence of a sulfuric acid radical at 200-300 deg.C to provide the plate magnetite particle. Thereby the aimed pore-free plate magnetite particle powder having 0.5-5mum average diameter and 1.5-6m<2>/g specific surface area and free from sintering is obtained. The obtained particle is preferably used as a material powder for electromagnetic absorption and shield material because of having excellent dispersibility in a vehicle or resin and being >=0.5mum particle. |
