The effect of grain size variations on magnetic properties in soft magnetic composites

Abstract

W pracy przeprowadzono analizę wpływu rozmiaru ziarna w magnetycznie miękkich materiałach kompozytowych na ich właściwości magnetyczne. W pracy wykorzystano próbki rdzeni cylindrycznych wykonanych przez autorów z mieszaniny żelaza z polichlorkiem winylu. Badania obejmowały wyznaczenie takich parametrów jak indukcja nasycenia, natężenie koercji i stratność. Zbadano ponadto wpływ częstotliwości magnesowania na stratność materiału.The application of soft magnetic composites increases in different branch of electric and electronic engineering. For this reason, it is very important to understand the micro-structural effects on their magnetic properties. The paper focuses on the effect of grain size variations of soft magnetic composites on their magnetic properties such as saturation flux density, coercive field strength, power losses etc. During research self-developed materials made of a mixture of pure iron and polyvinyl chloride were used. Three different grain sizes of Fe, namely: up to 50 μm, 50 μm – 100 μm and 100 μm – 150 μm were used in the study. All samples contained 99,5% Fe and 0,5% PVC. The grain size of PVC was 100 μm – 150 μm. The effect of grain size variations on the shape of hysteresis loops was also examined. In the paper it was proved, that the increase of grain size improves magnetic properties of ready-made cores, e.g. the power losses are decreased upon the grain size increase. The aforementioned effect is particularly visible for higher excitation frequencies e.g. at f = 400 Hz