铁基纳米晶软磁合金低频损耗的一般性质

General Properties of Low - frequency Power Losses in Fe - based Nanocrystalline Soft Magnetic Alloys

对五种铁基纳米晶软磁合金的三种主要原始磁状态,在10Hz≤f≤1000Hz和0.4T≤B_m≤1.0T范围内考查了每周损耗与f和B_m的关系。把总损耗P分解为磁滞损耗 P_(hyst),经典涡流损耗P_(c1)和过剩损耗P_(exc)之和。发现P_(hyst)与B^2_m和f成比例。P/f-f的行为在大约不超过120Hz的范围内呈现出明显的非线性性,而在远高于100Hz的不大于1000Hz的范围内,P/f-f行为大致表现出线性性。在直到l000Hz的范围内,在原始的高起始磁导率和低剩余磁通密度的状态中,P_(hyst)占优势;在高于100Hz的较宽范围内,高剩余磁通密度的状态中的P_(exc)占优势。应用损耗的统计理论来表示P_(exc)/f-f的行为。发现在大约120Hz以下,几个同时活动的“磁物”(Magnetic Object)数n随动态场H_(exc)按n=n_0+H_(exc)/H_0线性变化;在远高于100Hz的不超过1000Hz范围内,n服从形如n=n_0+(H_(exc)/H_0)~m的规律,其中1<m<2。场H_0之值原则上与显微组织及畴结构有关,对三种磁状态计算了H_0之值。

The dependence of the power loss per cycle on frequency f and amplitude flux density Bm has been investigated for the three main original magnetic states in five sorts of Fe - based nanocrystalline soft magnetic alloys in the ranges of 10≤f≤1000Hz and 0.4≤Bm≤1.0T. The total loss P is decomposed into the sum of the hysteresis loss Physt, the classical eddy current loss Pel and the excess loss Pexc. Physt has been found to be proportional to Bm2 and f. The behavior of P/f vs f clearly exhibits non - linearity in the range not more than about 120Hz, whereas the behavior of P/f vs f roughly shows linearity in the range far above 100Hz and not more than 1000Hz. In the range up to 1000Hz, Physt is dominant in the original high - permeability state and the state of low residual flux density, whereas Pexc in the state of high residual flux density is dominant in the wider range above about 100Hz. The framework of the statistical theory of power loss has been used for representing the behavior of Pexc/f vs f . It has been found that the number n of the simultaneously active ' Magnetic Objects' linearly varies as n = n0 + Hexc/H0 as a function of the dynamic field Hexc in the range below about 120Hz, whereas n approximately follows a law of the form n = n0+ (Hexc/H0)m with 1 < m < 2 in the range far above 100Hz and not more than 1000Hz. The values of the field H0 in principle related to the microstructure and the domain structure have been calculated for the three states.