Investigation of the frequency characteristics of composite iron powders with insulating oxide coatings

Abstract

This article discusses methods for studying the frequency characteristics of composite iron powders with insulating oxide coatings. The main dependences of hysteresis losses on induction for a full cycle at a frequency of magnetization reversal for various cross-sections of iron powders, sharply differing in the shape of the hysteresis curve and the values of the main magnetic characteristics, are studied, and also frequency dependences in the range of 50 Hz - 1 MHz of the figure of merit and inductance for samples based on composites are considered from powder Hoganes ASC100.29 after annealing in air, in water vapor and hydrogen at a temperature of 400 ° С for two hours. Based on the analysis of the dependencies, it can be explained by the fact that a material with a thin layer has a lower electrical resistivity, which means that the total electromagnetic losses will also be greater due to an increase in the contribution of losses to eddy currents. At the same time, the magnetic permeability at a frequency of 1 kHz differs by 30 units, and with an increase in the frequency to 1 MHz, it decreases by 10-15% for both materials. This makes it possible to use iron-based soft magnetic materials for electrical engineering.