Development of Corrosion Fatigue Testing Machine for Micro-Sized Specimens for Bio-MEMS

微机电系统（MEMS）器件有望作为生物MEMS（诊断和治疗设备）用于人体，并作为检测设备用于腐蚀性环境。在这种MEMS器件中使用的部件的尺寸被认为是微米量级。该尺寸小于常规金属和合金中的晶粒直径。这种微尺寸的材料的机械性能被认为是不同于散装材料。此外，腐蚀的影响被认为是更突出的，因为与大块试样相比，微米尺寸试样的比表面积更大。MEMS器件中可能存在尺寸也为微米量级的裂缝，因此裂缝腐蚀也很重要。因此，微尺度材料的腐蚀疲劳性能对设计腐蚀环境中使用的MEMS器件和微机械具有极其重要的意义。然而，很少有研究表明， ...更多信息 微尺寸材料的腐蚀疲劳性能。然而，在微尺寸试样上进行腐蚀疲劳试验存在一些困难。还需要澄清该方法存在的问题并找到解决方案。在本研究中，我们已经开发了一种微尺寸试样的腐蚀疲劳试验机，和微尺寸Ni-P非晶合金和304奥氏体不锈钢试样进行了腐蚀疲劳试验在空气和0.9%NaCl溶液中，以研究尺寸效应对腐蚀疲劳性能。用聚焦离子束加工Ni-P非晶态合金薄膜和304奥氏体不锈钢薄板，制备了尺寸为10 μ m × 10 μ m × 50 μ m的微束型试样。在空气中试验的试样的疲劳寿命超过10万次循环，而在腐蚀环境中试验的试样的疲劳寿命小于1万次循环。不同的环境对疲劳性能的影响进行了观察。并对该测试方法存在的问题及解决方法进行了讨论。少

MEMS (Micro electro mechanical systems) devices are expected to be used in human body as Bio-MEMS (diagnosis and treatment devices) and in corrosive environments as inspection devices. The size of components used in such MEMS devices are considered to be in the order of microns. This size is smaller than the grain diameter in conventional metals and alloys. Mechanical properties of such micro-sized materials are considered to be different from those of bulk materials. In addition, the effect of corrosion is considered to be more prominent, because the specific surface area of micro-sized specimens is larger compared with that of bulk specimens. Crevices, the size of which is also in the order of microns, may exist in MEMS devices and thus crevice corrosion is also important. Therefore, corrosion fatigue properties of micro-sized materials are extremely important to design MEMS devices and micro-machines used in corrosive environments. However, there have been few studies that investiga … More te corrosion fatigue properties of micro-sized materials. However, there are several difficulties in corrosion fatigue tests on micro-sized specimens. It is also necessary to clarify the problems for the method and to find their solutions. In this investigation, we have developed a fatigue testing machine for micro-sized specimens, and corrosion fatigue tests for micro-sized Ni-P amorphous alloy and 304 austenitic stainless steel specimens have been carried out in air and 0.9% NaCl solution to investigate the size effects on corrosion fatigue properties. Specimens of cantilever-beam-type with dimensions of 10 microns × 10 microns × 50 microns were prepared from a Ni-P amorphous alloy thin film and a 304 austenitic stainless steel thin sheet by focused ion beam machining. The fatigue life of the specimen tested in air was more than 100,000 cycles, while that tested in the corrosive environment was less than 10,000 cycles. Distinct environmental effects on fatigue properties were observed. Several problems and solutions for the testing method were also discussed. Less