导　　师： 王佳

学科专业： 081704

授予学位： 博士

作　　者： ;

机构地区： 中国海洋大学

摘　　要： 有机涂层由于能在金属表面形成一层有机膜阻止腐蚀性介质的渗入而被广泛的应用于海洋环境金属构件的腐蚀防护。但是,不可避免的,有机涂层会在众多复杂的海洋环境腐蚀因素的协同作用下逐渐劣化失效。在这些因素中,水、溶解氧及干湿交替是三个重要的影响因素。 有机涂层的吸水过程在涂层的劣化过程中扮演着重要角色,它是涂层屏蔽能力降低,界面腐蚀电化学反应及涂层剥离的前奏。研究发现,氧在涂层//金属界面区的还原是导致涂层剥离的重要因素。然而,当涂层处于干湿交替状态下时,涂层的渗水过程和氧在界面区的还原过程都将被强化。 本文的主要研究工作包括： /(1/)应用电化学阻抗谱技术,结合涂层失效过程的开路电位和表面形貌变化对比研究了全浸泡、4-4h和12-12h干湿循环条件下的有机涂层失效过程。根据阻抗谱响应建立了与各个阶段相对应的等效电路模型,通过解析参数分析了涂层劣化过程涂层性能和涂层下腐蚀反应发生发展的特征。 研究发现,根据涂层失效电化学阻抗谱响应特征,全浸泡和干湿交替条件下的有机涂层失效过程均可以分为三个主要阶段：涂层渗水阶段,基底金属腐蚀发生阶段和基底金属腐蚀发展与涂层失效阶段。根据涂层失效过程的阻抗谱结构,等效电路,腐蚀电动势,界面活性区面积百分比和涂层及涂层下的金属腐蚀形貌等多参数多方法分析了涂层的各个子腐蚀过程特征。与单一参数分析相比,这种多参数相关分析从多个不同角度分析涂层失效过程,能在多个平行信息比较印证下获得渗入可靠的研究结果。 与浸泡条件下的涂层失效过程相比,不同干湿循环比下的涂层失效过程呈现出较大的差别。4-4h干湿明显加速了涂层的失效过程,主要的加速阶段是界面腐蚀反应开始后的腐蚀反应起始阶段 Organic coatings are widely used to control the corrosion of steel structure, both to maintain appearance and to prevent loss of structural integrity. Thus, organic coatings should isolate the metal from the corrosive environments. However, organic coatings can be degraded under various service conditions, because they comprise polymeric material, leading to reduction of its anti-corrosive effectiveness. The degradation process of organic coatings is complex since it is affected by several factors. Under weathering exposure, wet-dry cycles, H2O and O2 are three critical factors for coatings degradation. The evolution of the water absorption process in an organic coatings immersed in a solution is a very important phenomenon because it precedes phenomena such as paint//metal interface loss of adhesion, electrochemical reactions and the reduction of the resistance to the passage of ions through the coating itself. Kinds of important effects of water penetration have been reported and the parameter of water up-take is often used for predicting anti-corrosive performances of organic coatings. It has been proven that the loss of adhesion between the organic coatings and the iron sample is induced by cathodic delamination which is caused by reaction products, like radicals from the paint//metal interface redox. The synergistic effect of oxygen reduction and water penetration was strengthened by wet-dry cycles during the coatings degradation and interface metal corrosion processes. The corresponding experimental results are listed as follows: /(1/) Under immersed and wet-dry cyclic conditions, the deterioration processes of the organic coating on carbon steel surface have been comparatively studied using electrochemical techniques. The wet-dry cycles are carried out by exposure to 4 h immersion and 4h drying /(4-4h cycles/) and 12h immersion and 12h drying /(12-12h cycles/), respectively. The immersion condition is carry out in a 3.5/% NaCl solution and drying at 298K and 50/% RH. According to the EIS res

关 键 词： 有机涂层 干湿循环 电化学阻抗谱 阵列电极

领　　域： [金属学及工艺] [金属学及工艺]