Micro-machining of thick permanent magnet by anodization technique and magnetic micro-machine for medicaluse

本研究旨在开发一种新的电沉积技术来制备厚永磁体薄膜，并将其应用于构建可放置在人体中并由外部磁场驱动的微型泵。为了采用电沉积法制备厚永磁体薄膜，努力引入电沉积过程中产生的磁致伸缩各向异性。证实了用糖精电沉积Co基材料在长径比大于20的细孔中产生了易于磁化轴垂直于厚膜的垂直各向异性。构建了两种不同结构的利用永磁体磁转矩的微泵。它们是由薄塑料板的振动和玻璃管表面与薄塑料板的机械摩擦驱动的。提高微泵的产量。采用Tb包覆钕铁硼磁体和柔性塑料薄膜。在钕铁硼磁体表面涂覆Tb，改善了因机械加工而恶化的磁各向异性。永磁体的磁转矩与饱和磁化成正比。采用残余磁化率提高20%以上的Tb包覆钕铁硼永磁体，可使微泵在60H时的输出功率提高约2倍。研究还发现，柔性塑料薄膜的应用使产量提高了约20%。利用上述研究成果，采用无旋转轴移动永磁体空间和截流阀，研制出了可置于人体体内，由外部磁场驱动的微型泵。其输出量可达到治疗胎儿脑积水所需的4cc/min。因此，所研制的微型泵有望应用于胎儿脑积水的治疗，将其附着在子宫内婴儿的头部，并根据手术程序驱动排出过量的脑脊液。少

This research aimed to develop a new electro-deposition technique to fabricate thick permanent magnet films and its application to construct a micro-pump which can be placed in a human body and driven by an external magnetic field.To fabricate the thick permanent magnet film by electro-deposition, efforts were made to introduce magnetostrictive anisotropy which is created during electro-deposition. It was confirmed that electro-deposition of Co based materials using saccharin into fine pores with aspect ration more than 20 created the perpendicular anisotropy having the easy magnetization axis normal to the thick film. Two different structured micro-pumps which utilized magnetic torque of permanent magnet were constructed. They are driven by vibration of thin plastic plate and by mechanical friction between surface of glass tube and a thin plastic plate. To increase output of the micro-pump. Tb coated NdFeB magnets and a flexible thin plastic film were applied. The coating of Tb on the … More NdFeB magnets improves the magnetic anisotropy which was deteriorated by mechanical processing. Magnetic torque of permanent magnets is proportional to saturation magentization. By using the Tb coated NdFeB permanent magnet with increased remanent magnetization more than 20%, it became possible to increase the out-put of micro-pump at 60H by about twice. It was also found that the application of the flexible plastic film increased the out-put by about 20%. Utilizing theses results together with adoption of a room for the moving permanent magnet without rotating axis and a valve for interception of reversing flow, we developed the micro-pump which can be placed in a human body and drive by external magnetic field from outside. Its output secures 4cc/min needed for cure of fetal hydrocephalus. So it is expected that the developed micro-pump would be applied for cure of fetal hydrocephalus by attaching it to a head of a baby in uterus and drive according schedule of operation to discharge the excessive cerebrospinal fluid. Less