Magnetic Powder Core and Iron Powder Core

Iron Silicon Aluminum Magnetic Powder Core and High Performance Iron Powder Core

 

Early magnetic powder cores were "bonded" metal soft magnetic cores made of iron-silicon-aluminium alloy magnetic powder. This kind of iron-silicon-aluminium magnetic powder core is often called "iron powder core". Its typical preparation process is: Fe-Si-Al alloy magnetic powder (market ingredient Fe:Si:Al=84%:10%:6%) is ground and flattened by ball milling and coated by chemical method, then added about 15wt% binder, mixed evenly, molded and solidified, and finally made into products by heat treatment (stress relief). This traditional "iron powder core" product mainly works in 20 kHz 200 kHz. They are widely used in high frequency electronic transformers and other electronic components because they have much higher saturated flux density, better DC superposition characteristics, near zero magnetostriction coefficient, noise-free operation, good frequency stability and high performance-price ratio than ferrites working in the same frequency band. Their disadvantage is that the non-magnetic filler not only produces magnetic dilution, but also makes the magnetic flux path discontinuous. Local demagnetization leads to the decrease of permeability. Therefore, it is mainly used in the work occasions where the requirements for Bm are very high and the requirements for permeability are not very strict.

 

The recently developed high performance iron powder core is different from the traditional iron-silicon-aluminium magnetic powder core. The raw material used is not alloy magnetic powder, but pure iron powder coated with insulating layer. The amount of binder is very small, so the magnetic flux density has been greatly improved. They work in the low and medium frequency band of less than 5 kHz, usually hundreds of hertz, which is much lower than the working frequency of ferrosilicon aluminium magnetic powder cores. The target market is to replace silicon steel sheets for motors with the advantages of low loss, high efficiency and easy to carry out three-dimensional design.