应用于近场通信的高磁导率NiCuZn铁氧体材料

针对近场通信(NFC)应用,通过改变材料中的Bi2O3含量和二磨后粉体活性,开发了一种高性能的Ni Cu Zn铁氧体材料。使用流延法制备长宽为125×125mm、厚度为100μm的铁氧体薄片。观察、测试了铁氧体材料的微观形貌、磁导率频谱以及铁氧体薄片的可读写距离。结果表明,铁氧体薄片的使用性能与铁氧体材料在13.56MHz时磁导率实部μ'、虚部μ"的值有关。通过改变材料中Bi2O3含量以及二磨后粉体活性,可获得致密度高、晶粒细小均匀,低频下μ'较高、μ"较低的铁氧体材料。在13.56MHz时磁导率实部μ'高于150,虚部μ"低于5。插入该铁氧体薄片后RFID天线紧贴金属的情况下可读写距离可以恢复到原始读写距离的80%。

High permeability NiCuZn ferrite applied in near field communication (NFC)

High performance NiCuZn ferrite was developed by changing the content of Bi2O3 and powder chemical activity for NFC applications. The final size of ferrite sheet with measurement 125mm×125mm×100μm was prepared by tape casting process The real part of permeability is higher than 150 while the imaginary part maintains lower than 5 at 13.56MHz. The microstructure and the magnetic spectrum of the ferrite and read/write distance of the ferrite sheet were observed and measured. The results show that the usability of ferrite sheet is related to the real and imaginary part of material permeability. Sintered ferrite with high density and fine grain could be obtained by changing the content of Bi2O3 and the powder chemical activity. As a result, the ferrite with high real part and low imaginary part of permeability could be obtained. Exactly, the real part of permeability was higher than 150 and the imaginary part lower than 5 at 13.56MHz. The read/write distance was restored to 80%of the primitive value after inserting the ferrite sheet between the RFID card and metal.