-
公开(公告)号：US20190228889A1
公开(公告)日：2019-07-25
申请号：US16337195
申请日：2017-09-29
摘要： An object of the present invention is to provide a magnetic powder having a narrow particle size distribution of epsilon-type iron oxide particles, and another object is to provide magnetic powder suitable for magnetic recording medium by improving particle size distribution, and provide epsilon-type iron oxide magnetic particles and related technologies in which a number average particle diameter of major diameters (D50) is 10 to 20 nm, a 90% cumulative particle diameter (D90) is 30 nm or less, and a geometric standard deviation (σg) of major diameters is 1.45 or less, which are obtained by TEM observation.
-
公开(公告)号：US20220344087A1
公开(公告)日：2022-10-27
申请号：US17762423
申请日：2020-09-29
发明人： Yasuto MIYAMOTO , Kazuhiro YAMAGA , Yuki MINEYAMA
摘要： A method for making an iron-based oxide magnetic powder includes adding raw material solution containing trivalent iron ions, or trivalent iron ions and ions of a metal element that partially substitutes Fe sites, and an alkaline aqueous solution for neutralizing the raw material solution to a reaction system to adjust the pH of the reaction system to 1.0 or higher and 3.0 or lower. Hydroxycarboxylic acid is added to the obtained reaction solution and thereafter the pH of the reaction system is neutralized to 7.0 or higher and 10.0 or lower. The obtained precipitate of a substituent metal element-containing iron oxyhydroxide is coated with silicon oxide and then heated, whereby an iron-based oxide magnetic powder is obtained with a reduced content of fine and coarse particles, a particle shape close to a perfect sphere, and particles of ε-iron oxide in which Fe sites are partially substituted by other metal elements.
-
搜索结果
2 条记录 (耗时 0.012 秒)
