典型材料磁各向异性的磁巴克豪森噪声评估方法

Magnetic anisotropy evaluation method using magnetic Barkhausen noise for typical materials

研究利用磁巴克豪森噪声对典型材料的磁各向异性进行评估,确定其易磁化轴和各向异性程度。首先,利用构建的实验系统测试了4种材料中不同方向磁巴克豪森噪声信号及其特征参量极图,研究了磁各向异性的描述模型及表示方法,基于三阶傅里叶级数展开式的模型在磁各向异性描述上具有普适性。其次,分析了测试条件对结果的影响,表明采用具有大跨距磁路的传感器更能准确测得材料的难、易磁化轴和各向异性程度。最后,利用不同磁化阶段提取的特征参数MP和RMS极图,良好地表征了4种材料的磁各向异性:硅钢的易磁化轴平行轧制方向,存在明显织构的有取向硅钢表现出最强的磁各向异性;管线钢中加工致磁各向异性较弱,主导机制是平均磁晶各向异性。

The magnetic Barkhausen noise(MBN) technique can be used to evaluate the magnetic anisotropy of typical materials and determine the magnetic easy axis and anisotropy degree. Firstly, the constructed experiment system was used to test the magnetic Barkhausen noise signals in different directions and the characteristic parameter pole figures of four materials. The description model and representation method of magnetic anisotropy are studied. The model based on the third-order Fourier series expansion has universality in the description of magnetic anisotropy. Secondly, the influence of test conditions on the results is analyzed, which shows that using the sensor with a large-span magnetic circuit can more accurately measure the magnetic hard axis and magnetic easy axis, and the anisotropy degree of the material. Finally, the characteristic parameter MP and RMS pole figures extracted in different magnetization stages are nicely used to characterize the magnetic anisotropy of the four materials. The magnetic easy axis of silicon steel is parallel to the rolling direction, and the grain-oriented silicon steel with strong texture exhibits strongest magnetic anisotropy. The processing-induced magnetic anisotropy in pipeline steel is weak, and the dominant mechanism is the average magnetocrystalline anisotropy.