| Metal magnetic powder core is a soft magnetic composite material with a magneto-electric conversion function. From the perspective of the use of frequency and power, the metal magnetic powder core is between metal soft material and ferrite, which is widely used in electronic communication, radar and power switch. FeSiAl magnetic powder core has a high saturation magnetic flux density, high permeability, good frequency characteristic, low loss and low price. It’s good to meet the development and application of electronic components trend of miniaturization, thining, lightweight and efficient.In this paper, FeSiAl magnetic powder cores were prepared by water-atomized FeSiAl powder. All samples were produced by warm compaction. Based on the characteristics of FeSiAl magnetic powder core and warm compaction, a multi-group experiment was designed in this paper to study the influence of surface insulation coating, warm compaction process and heat treatment on the powder core performance. Effect on core loss and permeability were investigated by modern analysis techniques including XRD, alternating current soft magnetic test equipment and precision magnetic components analyzer. The main conclusions are listed as follows:1.Surface insulation coating may improve the mechanical properties of the magnetic powder core, and reduce loss. Firstly, with the increase of phosphoric acid solution concentration from 0% to 5.0wt%, the sample density and permeability gradually decrease. But the core loss is decrease first and then increase at the same time. Secondly, with the increase of binder (Sodium silicate and 233 high temperature resistant silicone resin) content from 1.0wt% to 5.0wt%, the sample density, permeability and loss gradually decrease.When the concentration of phosphoric acid solution is 0.7wt% and the content of binder is 1.5wt%, the comprehensive performance of sample is the best which density after heat treatment is 5.737g/cm3, the effective permeability reach 134.0, and core loss reach15.04W/kg.2.Warm compaction is a critical step in FeSiAl powder core preparation. Firstly, stearate (Zinc stearate and Lithium stearate) and polyethylene glycol (PEG) are elected lubricant for warm compaction. The results show that Zinc stearate and PEG as composite lubricant are better than Lithium stearate and PEG. Secondly, with the increase of warm compaction temperature from room temperature to 140℃, the sample density gradually increase, while permeability increase first and then decrease. But, the core loss is decrease first and then increase at the same time. Finally, with the increase of pressing pressure from 600MPa to 1200 MPa, the variation trend of sample density, permeability and loss is similar to the last one. When the amount of composite luricant is 1.3wt% and the mass fraction of zinc stearate and PEG is 2:3, the comprehensive performance of sample compacted at 1100MPa/100℃ is the best which density after heat treatment is 5.749g/cm3, the effective permeability reach 134.0, and core loss reach 12.28W/kg.3.Heat treatment is the most sensitive procedure on performance of magnetic powder core. Firstly, with the increase of heat treatment temperature from room temperature to 690℃, the sample density gradually decrease, while permeability increase first and then decrease. But, loss is decrease first and then increase at the same time. Secondly, with the extension of the heat treatment time from 0.5h to 2h, the sample density gradually decrease, while permeability increase first and then decrease. But, loss is decrease first and then increase at the same time. When the heat treatment temperature is 630℃, the heat treatment time is 1h, the comprehensive performance of sample is the best which density after heat treatment is 5.737g/cm3, the effective permeability reach137.9, and core loss reach 12.63W/kg. |
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