Magnetic properties of Compressed amorphous powder cores and their application to DC-DC converters.

采用自旋水雾化新工艺制备了具有优异软磁性能的铁基非晶态粉末颗粒，该工艺具有较高的淬火速率和量产潜力。此外，这些非晶颗粒被玻璃细粉绝缘，并在低于结晶温度的相对高温条件下通过热压技术压制成环形，E形和锅形芯。制备的磁芯与市售的Sendust粉末磁芯相比，具有更好的磁性能。矫顽力减半，300 Oe时的磁通密度B_m提高30%。当B_m=0.1 T时，磁芯在100 kHz时的损耗为660 kW/m^3。前者与Sendust相当，后者低20%。得到的非晶磁芯应用于工作在100khz的DC-DC变换器。在输出功率高达300w时，测试的转换效率高于使用典型商用Sendust铁芯和单个间隙铁氧体铁芯的转换器。此外，还研究了感应式充电器的缝隙锅形铁芯的磁性能。对于间隙大于1.5mm的磁芯，非晶粉末磁芯的损耗低于铁氧体。

Fe-based amorphous powder particles with excellent soft-magnetic properties were fabricated by our new atomization process "spinning water atomization process(SWAP)", which has both a high quenching rate and mass- production potential. In addition, these amorphous particles were insulated by glass fine powder and pressed into toroidal, E- and pot-shaped cores by hot-pressing techniques at relatively high temperature conditions below crystallization temperature. The cores fablicated had superior magnetic properties compared with commercial Sendust powder core. The coercive force was half and the flux density B_m at 300 Oe was 30% higher. The initial permeability up to 1 MHz was about 90-110, and the core loss at 100 kHz for B_m=0.1 T was 660 kW/m^3. The former was comparable to that of Sendust and the latter was 20% lower. The amorphous cores obtained were applied to DC-DC converters working at 100 kHz. The conversion efficiency examined at out put power up to 300 W was higher than that of converters utilizing a typical commercial Sendust core and a single gapped ferrite core. Furthermore, the magnetic properties of gapped pot-shped core for inductive charger were also studied. For the cores with a gap of above 1.5mm, the loss of amorphous powder core exhibited lower than that of ferrite.