Study On Pizeomagnetic Property Of Fe_Based Amorphous Strips Under Normal Stress Condition

Fe-based amorphous strips are mainly applied to power electronic component and sensor fields. It is of great importance to study on piezomagnetic properties for power electronic component stability and development high performance sensors.In this paper, the piezomagnetic properties under point normal stresses for three different component strips, such as Fe78Sil3B9, Fe73.5CulNb3Sil3.5B9 and Fe72Co8Si15B5 strips, were systematically studied. At first, the measure problem of piezomagnetic properties under point stresses was studied, and then reliable testing system was designed and developed. Second, the effect of frequency, point stress, annealing condition and test temperature on piezomagnetic properties of amorphous strips was systematically studied. At last the change laws of piezomagnetic properties with frequency, stress, temperature and so on, had been found.The result of research shows that the piezomagnetic property is very well when testing frequency being above 1MHz. The piezomagnetic sensitivity increases with the increase of frequency and stress. The impedance change of casting and annealing states amorphous strips is very sensitive when stresses are from 0 to 0.12MPa and when testing temperature is 20℃. The piezomagnetic property is the best when testing temperature is from 30℃to 40℃, what is more, the stress maximum of high sensitivity range enlarges from 0.12MPa to 1.0MPs when testing temperature is 20℃. The piezomagnetic property of the strips will be improved by adjusting annealing process. Different component amorphous strips have themselves the best annealing process. The best annealing process of FeSiB strips is 200℃for 2h, and that of FeCuNbSiB and FeCoSiB strips is 300℃for 1h. Multiple repeat tests indicated that stress-impedance curves of strips were very consistent.