MECHANO-ELECTROCHEMISTRY OF MICRO-SURFACE AREA OF MATERIALS

在pH 8.4的硼酸盐溶液中，对电化学控制的单晶铁(100)表面进行了纳米压痕试验，测量了载荷-深度曲线，并由此评价了铁表面的硬度和弹性模数等力学性能，为建立机械电化学提供了基础知识。铁表面的硬度随纳米表面积位置的不同而波动。然而，在钝化电位区，硬度的平均值在0.25V处出现最小值。在0.25V以上的电位下，平均硬度随电位的增加而线性增加，即钝化膜的厚度。利用平均硬度与薄膜厚度之间的线性关系，可以将薄膜本身的硬度与铁基的硬度区分开来。此外，还对在1.0V下钝化的单晶铁(100)和(110)表面进行了纳米压痕测试，这些表面在pH8.4的硼酸盐溶液中对…进一步考察了硬度对表面结晶取向的影响。然而，单晶铁(100)和(110)表面的硬度没有显著差异。测量了多晶钛在不同电解液溶液中阳极氧化后表面的硬度随阳极氧化膜形成电位的变化。当成膜电压达到8V时，硬度随成膜电位的增加而增加，在8V以上，硬度迅速下降，此时薄膜将发生局部击穿。此外，在硫酸中阳极氧化处理的钛表面硬度最高。用激光偏转法测量了钛阳极氧化膜中产生的应力，研究了膜中应力与硬度的关系。钛阳极氧化膜在硫酸中产生的压应力最大。由此发现，压应力与硬度之间有很好的相关性。在8V以上的电势下，阳极氧化膜发生局部击穿，压应力部分释放。在电位高于8V时，硬度的快速下降是由于阳极氧化膜的局部破裂导致了压应力的部分释放。较少

Nanoindentation tests were performed for the single crystal iron (100) surfaces electrochemically controlled in pH 8.4 borate solution to measure the load-depth curves from which the mechanical properties such as hardness and elastic modulus of the iron surfaces were evaluted to obtain the fundamental knowledge for estabilshment of mechano-electrochemistry. The hardness of the iron surfaces was fluctuated depending on the position of nano-surface area. The average value of hardness, however, took a minimum at 0.25 V in the passive potential region. At the potential above 0.25 v, the average hardness increased linearly with increasing the potential, I.e., the thickness of passive film. The hardness of film itself could be separated from that of the substrate iron by using the linear relation between average hardness and film thickness. Moreover, the nanoindentation tests were performed for the single crystal iron (100) and (110) surfaces passivated at 1.0 V in pH 8.4 borate solution to … More investigate the depedence of hardness on crystal orientation of the surface. However, no significant differences in hardness was observed between single crystal iron (100) and (110) surfaces.The hardness of the polycrystalline titanium surfaces subjected to anodic oxidation in various electrolyte solutions was measured as a function of formation potential of anodic oxide film. The hardness increased with increasing the film formation potential up to 8 V. The hardness decreased rapidly above 8 V at which the local breakdown of the film would take place. Moreover, the largest hardness was observed for the titanium surfaces subjected to anodic oxidation in sulfuric acid. The stresses generated in the anodic oxide film on titanium were measured by a laser-beam deflection method to investigate the relation between stress in the film and hardness. The largest compressive stresses were generated in anodic oxide film on titanium in sulfuric acid. Therfore, it is found that there is a good correlation between compressive stress and hardness. The partial release of the compressive stresses were observed at the potential above 8 V at which the local breakdown of anodic oxide film took place. The rapid decrease in hardness at the potential above 8 V was ascribed to the partial release of compressive stress ue to local breakdown of anodic oxide film. Less