| 摘要 |
PURPOSE:To obtain an oxide magnetic material having uniform and fine particle diameter, excellent processability, and high electrical resistance, by adding less than specific amounts of SrCO3 and GeO3 to an Mn-Zn ferrite composed of specific molar ratios of Fe2O3, ZnO and MnO, and pressing the composition with a hot hydrostatic press (HIP), thereby reducing the void volume below a specific level. CONSTITUTION:SrCO3 and GeO3 are added to an Mn-Zn ferrite composed of 50-65mol% Fe2O3, 5-30mol% ZnO and the remaining part of MnO. The amounts of SrCO3 and GeO3 are <=0.5wt% (especially 0.01-0.1wt%) each. The mixture is crushed with a ball mill, dried, formed, and subjected to the primary baking. The baked product is pressed with an HIP, e.g. in an Ar atmosphere at about 1,200 deg.C and about 1,500 atm to reduce the void volume to <=0.5%. The product may contain <=0.5wt% subsidiary components selected from oxides of K, Cr, Ti, Co, Zr, In, Sn, Y, Na, Ni, Si, Mg, Cu, Te, Cd, or Ta, and Cl, C and S. |
