| 摘要 |
PURPOSE:To obtain a sintered magnetic substance of high magnetic flux density with less iron loss by a method wherein iron or iron-based alloy powder is compacted within a given mold under pressure to have the particular density, and an oxide insulating film is produced to be coated thereon. CONSTITUTION:Iron or iron-based alloy powder of the required amount is filled in a mold for forming the desired electromagnetic part, etc., compacted under pressure to have the average density of 6.0-7.4gr/cm<3> and then heated up to 600-1,100 deg.C in non- oxidizing atmospheric gas. Subsequently or separately, the iron or iron-based alloy powder is subjected to the dew point control of atmospheric gas, steam treatment, etc. in such a temperature range as producing triiron tetroxide to apply an oxide insulative coating thereon. In case of the average density less than 6.0gr/cm<3>, the size of compacts such as cores resulted through forming and sintering must be enlarged several times in order to obtain the magnetic flux density comparable to that of the conventional iron- based core, so that it is not practical. In case of the average density higher than 7.4gr/cm<3>, it is impossible for the conventional pressurizing method to raise the density higher than 7.4gr/cm<3> by using the pressurizing apparatus holding the compact from above and bottom, so that the treatment process such as remachining is required. |
