IRON-BASED OXIDE MAGNETIC POWDER AND MANUFACTURING METHOD THEREOF

To provide an iron-based oxide magnetic powder composed of ε-iron oxide particles in which some of Fe sites are replaced with other metal elements, which has good thermal stability and a small change in radio absorption even in a high temperature environment, a radio wave absorber using the iron-based oxide magnetic powder, and a power powder using the iron-based oxide magnetic powder and a manufacturing method of the same.SOLUTION: Phosphorus-containing ions are caused to coexist when a silicon oxide is coated using a silane compound in a precipitate of iron hydroxide containing a substituted metal element which is produced by neutralizing an acidic aqueous solution containing trivalent iron ions and metal ions which replace some of Fe sites, such that an iron-based oxide magnetic powder can be obtained that is composed of ε-iron oxide particles, and in which the thermal stability is good, the change in the amount of radio wave absorption is small even in a high temperature environment, and some of the Fe sites are replaced with other metal elements.SELECTED DRAWING: Figure 2 【課題】熱的安定性が良好で、高温環境でも電波吸収量の変化が小さい、Ｆｅサイトの一部が他の金属元素で置換されたε酸化鉄の粒子からなる鉄系酸化物磁性粉、当該鉄系酸化物磁性粉を用いた電波吸収体、ならびに当該鉄系酸化物磁性粉を用いた圧粉体およびその製造方法を提供する。【解決手段】３価の鉄イオンおよびのＦｅサイトの一部を置換する金属のイオンを含む酸性の水溶液を中和して生成する置換金属元素を含む鉄水酸化物の沈殿物に、シラン化合物を用いてシリコン酸化物を被覆する際にリン含有イオンを共存させることにより、熱的安定性が良好で、高温環境でも電波吸収量の変化が小さい、Ｆｅサイトの一部が他の金属元素で置換されたε酸化鉄の粒子からなる鉄系酸化物磁性粉が得られる。【選択図】図２