乾壓及射出成形軟磁材料之磁性質

Abstract

隨著科技的進步，磁性材料在不管是電子零件或是日常生活的家用電器中都隨處可見，而這類零件的形狀通常都相當複雜，因此很適合以金屬粉末射出成形來製造。本實驗將重點放在鐵基合金的軟磁材料，一般常見的鐵基軟磁材料包括純鐵、鐵磷合金與鐵矽合金，因此本實驗將這三種合金利用1350oC的高溫將試片燒結至高密度，利用氫氣、裂解氨與真空等燒結氣氛將材料的雜質例如碳、氧含量降低，以期望獲得軟磁性佳的磁性材料。 結果顯示，Fe-0.45%P鐵磷合金在裂解氨氣氛中1350oC燒結一小時後，其Bmax可到達17,700gauss，HC可到達0.4 Oe，μmax可到達12,500gauss/Oe的磁性質，電阻率可到達17μΩ．cm，且具有良好的延展性。鐵矽材料雖然磁性質較鐵磷合金差，但其電阻率較高，Fe-5.0%Si在裂解氨氣氛中1350oC燒結一小時後其電阻率可到達63μΩ．cm，能降低磁性材料在交流電場中的渦電流損。 另外，本實驗亦嘗試探討Fe-P-Si三元合金系統的磁性質，發現將1wt%的矽添加到OM-0.45%P中，可將電阻率提升至31μΩ．cm，且同樣保有良好的磁性質與延展性，其Bmax可到達17,200gauss，HC可到達0.54 Oe，μmax可到達12,200gauss/Oe，因此為本實驗中最佳的磁性材料成分。

Magnetic materials are important in many industrial applications today. The shape of this kind of magnetic materials is usually complicated, therefore metal injection molding (MIM) is very suitable to make magnetic products. The objective of this study was to examine the properties of pure iron, iron-phosphorus, and iron-silicon magnetic materials. The sintering temperature need in this study was 1350oC. The sintering atmosphere was pure hydrogen, cracked ammonia, vacuum with which the amount of carbon and oxygen in the material was reduced and thus good magnetic properties obtained. The results showed that Fe-0.45%P alloy which was sintered in cracked ammonia at 1350oC for 1hr had good elongation and could attain a Bmax of 17,700gauss, HC of 0.4 Oe, μmax of 12,500gauss/Oe, and resistivity of 17μΩ．cm. Although the magnetic properties of Fe-Si alloy was not as good as Fe-P alloy, but it could give a higher resistivity. Fe-5%Si sintered in cracked ammonia at 1350oC for 1hr could attained a 63μΩ．cm resistivity, which reduced a low eddy current loss in AC applications. The Fe-P-Si ternary system was also examined in this study. The results showed that adding 1wt%Si into Fe-0.45%P alloy could increase the resistivity from 17μΩ．cm to 31μΩ．cm, and good elongation and magnetic properties were retained. It could attain a Bmax of 17,200gauss, HC of 0.54 Oe, and μmax of 12,200gauss/Oe. So it is the best magnetic material composition investigated in this study.