Strictly speaking, metal magnetic powder cores are specialized in manufacturing inductance devices. The differences between metal magnetic powder cores and ferrites are listed below.
1) Metal magnetic powder cores have higher Bs and lower permeability. At the same time, the magnetic bias curve is quasi-linear, and can withstand larger DC bias, because the core is not easy to saturate.
2) The uniform distribution of air gap in metal magnetic powder core can avoid the local loss caused by the opening of air gap.
3) Metal magnetic powder cores react more slowly than ferrites to environmental change (temperature change and mechanical impact), which is determined by the characteristics of metal and ceramic materials themselves. The former has a high Curie temperature, and its permeability changes very little in the working range, so its reliability is better than that of the latter. This is also the reason why metal magnetic powder cores are widely used in military industry. The working temperature range of metal magnetic powder core is wider than that of ferrite, and some materials can even work at 300 C.
4) The design method of metal magnetic powder core is relatively simple, especially in the design of power choke, it is almost unnecessary to test dynamic indicators to verify the design. Due to the poor stability of ferrite materials, different designs are needed for different situations, and dynamic tests are needed.