关键词: 不锈钢, 微电极, 点腐蚀, 机理, 研究方法

Abstract: Abstract Differing with the scanning microelectrode techniques, which scan microelctrode closely to the interface of electrode/electrolyte and make electrochemical imaging in a lateral spatial resolution, the technique of microelectrode with a micron diameter is of very high timeresolution and ratio of signal/noise in electrochemical measurements. The microelectrode technique allows doublelayer capacitance and background current for a microelectrode to be drastically reduced due to the exposed area of a microelectrode is usually 6～8 orders of magnetite lower than that of a conventional electrode with largescale exposed area. Microelectrode was recently developed as a new powerful electrochemical technique and widely used in the studies of electrochemical kinetics, electrodeposition, electroanalysis and batteries. However, most of the microelectrodes was limited with the novel metals, such as Pt and Au, and only a little of work has reported on using microelectrode in corrosion research. In the present work, the microelectrode technique was developed to study the initiation and propagation of pitting corrosion of 18/8 stainless steel. The insight into the dissolution process of inclusion defects at the anodic potential of active dissolution and the dynamic behavior of growth and ceases for the micropitting during its development was attained. Microelectrode technique may offer a numbers of advantages for further recognizing the mechanism of pitting corrosion: to catch the fast and weak signal in an early stage of pitting initiation because of extreme low in both of doublelayer capacitance and background current for a microelectrode; to clarify the dependence of pitting nucleation on the inhomogenious defects; and to follow the propagation process for a simulated single pitting corrosion.