Magnetic properties of high-efficiency core materials NC-M3 and NC-M4

Abstract

High-efficiency core materials—New Core NC-M3 and NC-M4— with very low core loss and high permeability have been developed to improve the magnetic properties of conventional magnetic lamination steels. The magnetically favorable crystalline textures are enhanced through the addition of Mn and Sn to low-silicon steel. By adding Mn, particularly more than ~ 1.0 wt.%, to low- silicon steel, a decrease in (111) plane crystals and an increase in (110) and (100) plane crystals are achieved. Moreover, by adding Sn to low- silicon steel containing Mn, the decrease in (111) plane crystals and the increase in (110) plane crystals are more significant. The most suitable amount for the addition of Sn is ~ 0.1 wt.%, because excessive Sn content prevents normal grain growth in steels and makes magnetic properties, particularly core loss, inferior. Typical magnetic properties of NC- M3 (0.47- mm thickness) are 1.70 W/lb in W_15/60 and 3000 Gauss/Oe in µ15/60, and those of NC- M4 (0.47- mm thickness) are 1.57 W/lb in W_15/60 and 3000 Gauss/Oe in µ15/60. The lower core losses are attained mainly by reducing hysteresis loss. The superior magnetic properties of NC- M4 compared to NC- M3 are due to the fact that the steel is cleaner and has undergone sufficient hot band annealing during manufacturing.