| 摘要 |
PROBLEM TO BE SOLVED: To obtain a ferrite material excellent in the temperature characteristics in which the temperature coefficient of its inductance L or magnetic permeability μ is in a desired range by admixing CaO and Al2 O3 to the specific main component in a Ni-Zn ferrite. SOLUTION: The content of Fe2 O3 is set to 45-50mol% expressed in terms of oxide thereby preventing the temperature properties from worsening due to reduction in the magnetic permeability to inhibit the reduction of the Q value. ZnO content is set to 28-33mol% to inhibit the deterioration of magnetic permeability and the reduction of the Curie point. In order to inhibit the Curie point and the magnetic permeability from falling, NiO content is set to 12-17mol%. The content of CuO is set to 3-8mol% because <=3mol% deteriorates its sintering properties, while >=8mol% forms a liquid phase in the sintered compact to readily grow granules thereby reducing the Q value. Less than 1.7 pt.wt. of CaO and 0.05-0.5 pt.wt. of Al2 O3 are added to 100 pts.wt. of these components to prepare the objective ferrite material having a temperature coefficient of the magnetic permeability of <=±500ppm/ deg.C within the temperature ranges of -20-20 deg.C and 20-80 deg.C, respectively. |
