导　　师： 王佳

学科专业： G0702

授予学位： 博士

作　　者： ;

机构地区： 中国科学院海洋研究所

摘　　要： 尽管大气腐蚀研究已有上百年历史,但仍有很多问题尚未澄清.近来,我们发现在一定的相对湿度下,在易被腐蚀的金属表面上预先形成一小滴腐蚀性强的溶液时,马上在这滴小液滴的周围有直径为1~10微米的微液滴出现并向四周扩展.当金属是耐腐蚀性材料或所加液滴是腐蚀性很弱的溶液时,这种现象不出现.显然,微液滴现象与大气腐蚀密切相关.本文通过考察影响微液滴形成和扩展的因素、极化和未极化时微液滴的形成和扩展特征、微液滴的酸碱性和电位分布特点等实验确定了微液滴现象与大气腐蚀之间的关系.结合sem+eds实验结果,提出了微液滴形成和扩展的可能机制. Atmospheric corrosion is the most widespread corrosion problem known to mankind, and can be defined as the corrosion of metal materials exposed to air and its pollutants, rather than immersed in a solution. The process of atmospheric corrosion is accelerated with the formation of an electrolyte droplet, which was named as main-droplet here, or a thin electrolyte layer through the adsorption of water vapor by the deposited salt particle at certain relative humidity. The formation of the electrolyte droplet or thin electrolyte layer electrochemically changes the surface situation of materials from homogeneity to heterogeneity. Therefore, a considerable potential difference or corrosion current is established in the electrolyte droplet or thin electrolyte layer, and the atmospheric corrosion is ignited and accelerated due to the existence of corrosion cell. Although much information has obtained about the atmospheric corrosion process, yet even today it is not fully understood. Recently, a lot of micro-droplets, 1~10μm in diameter, were observed around the edge of main-droplet formed by the deliquescence of salt particles deposited on metals in atmosphere. Some of characteristics of micro-droplets were that they were caused by the type of main-droplet and formed only when the metal can be corroded for the main-droplet. Obviously, the phenomenon of micro-droplets formation may be related to the atmospheric corrosion process. In this paper, the characteristics of the formation and spreading of micro-droplets were studied in detail based on the pH and potential distributions of micro-droplets in the humidity-controlled chamber. The relations between the micro-droplets formation and the atmospheric corrosion were also investigated with the scanning Kelvin probe, the electrochemical polarization and the surface analyses of SEM + EDS. The probable mechanism was also discussed for the formation of micro-droplets. The corresponding experimental results were listed as follow. /(1/) The phenomen

关 键 词： 主液滴 微液滴 电化学极化 大气腐蚀 形成机制

领　　域： [金属学及工艺] [金属学及工艺]