盐水入侵与干湿交替共同作用下船闸金属结构腐蚀特征研究

河口船闸金属结构服役于盐水上溯入侵及船闸在运行过程中由于频繁灌泄水而产生的高频干湿交替腐蚀环境，船闸金属结构(闸阀门、系船设施等)在该特殊环境下的腐蚀特征尚未知。通过开展盐水高频干湿交替下钢试样腐蚀试验，分析不同氯盐浓度、干湿制度下钢试样腐蚀形貌、腐蚀速率的变化规律。在此基础上，开展聚氨酯、环氧煤沥青、氯化橡胶防腐涂料在该特殊腐蚀环境下的适应性研究。结果表明：盐水高频干湿交替作用会显著加速钢材的腐蚀速率，其加速程度随干燥时间的增大有所减小；碳钢在盐水高频干湿交替环境中的腐蚀速率为淡水环境的5.0～6.0倍，为海洋潮汐环境的1.5～2.0倍。根据各类防腐涂料在上述特殊腐蚀环境下的宏观形貌及附着力指标实测值，结合技术经济分析，建议采用氯化橡胶类涂料作为河口船闸金属结构的防腐材料。

Corrosion characteristics of metal structure for ship lock under saltwater intrusion and drying-wetting alternation

The metal structure of estuarine ship locks is used to resist upstream saltwater intrusion and the corrosive high-frequency drying-wetting alternating environment caused by frequent water filling and emptying during the operation of ship locks. The corrosion characteristics of the metal structure (gate valve, mooring facilities, etc. ) in this special environment, however, are unknown. Therefore, this paper conducts corrosion tests of steel samples under high-frequency drying-wetting alternation of saltwater and analyzes the change rules of corrosion morphologies and corrosion rates of steel samples under different concentrations of chlorine salt and different drying and wetting regimes. On this basis, it investigates the adaptability of the anti-corrosive coatings of polyurethane, epoxy coal tar pitch, and chlorinated rubber in this special corrosive environment. The results show that the high-frequency wetting-drying alternation of saltwater can considerably accelerate the corrosion rate of steel, and the acceleration degree decreases with the increase in drying time. The corrosion rate of carbon steel in the high-frequency drying-wetting alternating environment of saltwater is about 5. 0 to 6. 0 times that in a freshwater environment and 1. 5 to 2. 0 times that in an ocean tidal environment. According to the measured macro-morphology and adhesion of various anti-corrosive coatings in the above special corrosive environment and the technical and economic analysis, it is suggested that chlorinated rubber coatings should be used as anti-corrosive materials for the metal structure of estuarine ship locks.