Study on the Microstructure and Magnetic Domain Struture of the Soft Magentic Alloy 1J50

1J50 alloy is one of the major iron–nickel compositions,well-known for high flux density, low coercivity and high saturation induction.In this study,the microstructure and magnetic domain struture of the soft magentic alloy 1J50 before and after heat treatment (HT) were studied using scanning electron microscopy (SEM)、transmission electronmicroscopy (TEM) and magnetic force microscope (MFM). The results showed that grain size and domain size were small before HT,there was high-density dialocation in the alloy.After HT,grain size increased, the internal stress, dislocation and other defects were reduced,magnetic domains became wider,the number of the domain decreased and the exchange energy between the magnetic domain reduced,leading to the decrease of the coercivity and increase of permeability.It was also found that the curie temperature was not changed after heat treatment. The research can provide theoretically a reliable way for preparing Fe-Ni soft magnetic alloys with high performance.