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

点击翻译按钮获取中文摘要

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