| 摘要 |
A unique class of high efficiency heating agents consisting of fibers and in particular ferromagnetic fibers for use in alternating magnetic fields is disclosed which have remarkably and unexpectedly high heating efficiencies. The fibers operate efficiently at lower field intensities; at lower frequencies; and, with smaller diameters (related to skin depths) than prior art technologies. The heating agents may be formed from a variety of materials, for example fibers including ferromagnetic material selected from the group consisting of: iron, nickel, cobalt, chromium and alloys thereof; preferably, the fibers can be selected from the group consisting of: carbon steel fibers, magnetic stainless steel fibers, nickel fibers, ferromagnetic coated electrically conductive fibers, ferromagnetic coated electrically nonconductive fibers. The fibers, which are associated with a host material to be heated, are sized, in accordance with skin effect theory, to heat effectively at a frequency which is substantially higher that the actual frequency to be utilized. The fibers have lower apparent density and/or smaller diameters and/or higher surface areas and/or substantially higher heating efficiency than powder of the same ferromagnetic composition for operation at a given frequency.
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