FERRITE, FERRITE CORE AND METHOD FOR PRODUCING FERRITE CORE

PROBLEM TO BE SOLVED: To provide ferrite enhancing a value of relative initial magnetic permeability at 1 kHz and having high impedance characteristics in the vicinity of 150 kHz, to provide a ferrite core and to provide a method for producing a ferrite core.SOLUTION: The ferrite core is composed of ferrite having an average crystal grain size after sintering of not less than 25 μm to not more than 50 μm and a sintering density of not less than 5.03 g/cc to not more than 5.05 g/cc and has a cross-sectional area perpendicular to a magnetic path of not less than 10 to not more than 80 mm. The method for producing a ferrite core comprises a mixing step, a calcination step, a disintegration step, a molding step and a sintering step, where the mixing step includes a step of mixing raw material powder until the mixed grain size D50 of the raw material powder attains 0.50 to 0.68 μm. The ferrite satisfies a relationship of 0.4≤σ/X≤0.8, when an average crystal grain size is represented by X, and a standard deviation of the average crystal grain size is represented by σ.SELECTED DRAWING: Figure 2 【課題】１ｋＨｚにおける比初透磁率の値を向上させ、１５０ｋＨｚ近傍において高いインピーダンス特性を有するフェライト、フェライトコア、およびフェライトコアの製造方法の提供。【解決手段】焼結後の平均結晶粒径が２５μｍ以上、５０μｍ以下であり、焼結密度が５．０３ｇ／ｃｃ以上、５．０５ｇ／ｃｃ以下であるフェライトで構成し、磁路に垂直な断面積が１０〜８０ｍｍ２以下であるフェライトコア。また、混合工程、仮焼工程、解砕工程、成形工程、および焼結工程を含むフェライトコアの製造方法であって、混合工程において、原料粉末の混合粒径Ｄ５０を０．５０〜０．６８μｍに混合する工程を含むフェライトコアの製造方法。前記平均結晶粒径をＸ、前記平均結晶粒径の標準偏差をσと表した場合に、０．４≦σ／Ｘ≦０．８の関係が成り立つ、フェライト。【選択図】図２