Microscopic In-situ Evaluation of Corroding Surface of Film

在本研究中，石英晶体微天平（QCM），相位检测干涉显微镜（PDIM）的可用性。对共聚焦激光扫描显微镜（CLSM）和扫描电化学显微镜（SECM）这两种被认为是薄膜腐蚀表面显微原位评价的有力方法进行了详细的研究。对QCM振动模式的频率分析表明，在空气中相对湿度为30%的临界条件下，金表面MgCl_2盐膜的质量明显下降，这是由于薄膜吸水导致MgCl_2盐膜由固相转变为液相，从而降低了QCM的振动能量损失，表明QCM作为相变传感器具有广阔的应用前景。在HF溶液中化学蚀刻p型Si表面的PDIM观测表明，蚀刻速率取决于Si的比电阻率，表面粗糙度或形貌可以定量地评价为蚀刻时间的函数。用PDIM还观察到，电抛光铝表面随机分布着小斑点，这些小斑点与随后在电抛光表面形成的阳极氧化膜缺陷有关。将CLSM应用于具有可见光的多孔硅层（PSL）上，成功地对其三维形貌进行了无损观察。用CLSM同时测量了相应的发光形态，发现可见发光均匀地从PSL的整个深度发出。采用SECM法对钛表面形成的阳极氧化膜（TiO_2）缺陷部位进行了评价。将覆盖有TiO_2薄膜的Ti电极浸入含有Br^-离子的H_2SO_4溶液中，将Ti电极的电位控制在Br^-离子的氧化电位，Br^-离子仅在TiO_2薄膜的缺陷部位氧化生成Br_2。同时，将电极电位控制在Br_2还原电位处的探针电极（碳纤维）扫描到Ti电极表面，测量阴极电流的分布图。根据电流分布图可以确定TiO_2膜缺陷部位的位置。应用SECM仍在继续评价铁表面钝化膜的均匀性。通过以上实验结果，可以全面了解QCM、PDIM、CSLM和SECM对膜腐蚀表面微观原位评价的有效性。少

In this study, the availabilities of Quartz Crystal Microbalance(QCM), Phase Detection Interferometric Microscope (PDIM). Confocal Laser-Scanning Microscope (CLSM), and Scanning Electrochemical Microscope (SECM), which are regarded as powerful methods for microscopic in-situ evaluation of corroding surface of film, are examined more in detail.The frequency analysis of QCM vibration mode has revealed that the apparent decrease in mass of MgCl_2 salt film on gold at a critical relative humidity of 30 % in air results from the decrease in vibrational energy loss of QCM due to the phase transition of MgCl_2 film from solid to liquid which is caused by water absorption into the film, suggesting that QCM is promising as a sensor of phase transition.The PDIM observation of p-type Si surface subjected to chemical etching in HF solution has indicated that the etching rate depends on the specific resistivity of Si and the surface roughness or topography can be evaluated quantitatively as a funct … More ion of etching time. It has been also observed with PDIM that small spots are randomly distributed on electropolished aluminum surface and are associated with defects in the anodic oxide film formed subsequently on the electropolished surface.The application of CLSM to a porous Si layr (PSL) with visible luminescence has succeeded in observing nondestructively the three-dimensional morphology of PSL.The simultaneous measurement of the corresponding luminescensce morphology with CLSM has revealed that the visible luminescence emits uniformly from the whole depth of PSL.The SECM has been applied to evaluate the defect site of anodic oxide film (TiO_2) formed on Ti. When Ti electrode covered with TiO_2 film was immersed in H_2SO_4 solution containing Br^-ions and the potential of the Ti electrode was controlled at the potential of oxidation of Br^-ions, the oxidation of Br^-ions proceeded only on the defect site of TiO_2 film to produce Br_2. Simultaneously, the probe electrode (carbon fiber), the potential of which was controlled at the potential of reduction of Br_2, was scanned just over the Ti electrode surface to measure the distribution map of cathodic current flowed through the probe electrode. The location of defect site of TiO_2 film could be determined from the current distribution map. The application of SECM still continues to evaluate the uniformity of passive film on Fe.The comprehensive understanding of the availabilities of QCM,PDIM,CSLM,and SECM for microscopic in-situ evaluation of corroding surface of film could be performed with the above experimental results. Less