| 摘要 |
PURPOSE:To obtain an amorphous core for common mode choke, which is superior in characteristics to a low-level noise to a ferrite core for common mode choke and is equal or more with a Co group amorphous core for common mode choke in stability with time and is superior to the Co group amorphous more, by a method wherein an amorphous alloy having a specific composition is used as the material for the amorphous core for common mode choke. CONSTITUTION:An amorphous alloy having a composition, which is shown by a compositional formula =Fe100-x-y-zMxSiyBz (where the M is at least one kind of an element to be chosen out of the group of Ti, Zr, Hb, V, Nb, Ta, Cr, Mo, W, Mn, and Ni) and has the relations of 0.1<=x<=8, 10<=y<=18 and 8<=z<=9.5 (atomic %), is used as the material for the amorphous core for common mode choke. The Fe is essential in the composition and is needed for enhancing the magnetic properties of the amorphous alloy. The M is an essential element for improving the variation with time and for improving the noise attenuation characteristic. However, when the content (x) of the M is not more than 0.1 atomic %, the M has no effect on the improvement of the variation with time and the improvement of the noise attenuation characteristic and when the content (x) is larger than 8 atomic %, a marked drop in the saturated magnetic flux density and the Curie temperature is brought. Accordingly, it is not desirable for the content (x) to exceed 8 atomic %. When the amorphous alloy having a board thickness of 20mum or less is used, the noise attenuation characteristic of a high frequency (500kHz or more) is especially improved. As a result, more favorable results can be obtained. |
