Effect of Powder Particle Surface Treatment on DC Magnetic Properties of Compacted Iron Cores

Soft magnetic iron finds practical use in many applications, such as electromagnets and relays. In order for these devices to work effectively, it is necessary to know their dc magnetic properties. Soft magnetic compacted powder cores possess lower permeability than powder particles from which they were prepared, due to the inner demagnetization factor caused by the existence of pores in the core structure. The aim of the work was to determine the effect of surface mechanical treatment of iron powder particles of two different size fractions, leading either to an increase in the demagnetization factor or to a positive effect on the dc magnetic properties of the resulting compacted cores. For samples prepared from smaller powder particles, we found, that despite the increase in inner demagnetization factor as a result of the smoothing procedure, the differential relative permeability increased, and total energy loss decreased.