摘要
利用电弧喷涂工艺在钢铁基体表面全部或部分地喷涂铝涂层 ,考察了涂层对裸露于腐蚀介质中钢材基体的防护作用 ,以失重法计算了静态腐蚀速度与动态腐蚀速度 ,并探讨了腐蚀机理。用扫描电镜 (SEM )对铝涂层腐蚀前后的外表形貌进行了观察 ,并测定了涂层的孔隙率。研究结果表明 ,当腐蚀介质为NaCl溶液 (其质量分数为5 0 % )、实验温度为 (5 0± 1)℃、介质流速为 1m/s时 ,铝涂层的动态腐蚀速度为静态腐蚀速度的 2倍。裸露于腐蚀介质中的钢铁面积增大 ,促使阴极去极化过程快速进行 ,腐蚀速度加快 ,涂层防护寿命缩短。涂层表面上氧化膜的自愈能力及涂层表面上沉积的白锈具有阻碍铝作为阳极牺牲从而保护阴极的功效。涂层中的贯通孔隙对削弱铝涂层的防护作用 ,随腐蚀过程进行而逐步减弱。
Aluminum coating was sprayed on all or part of the steel matrix using arc spraying technique. The effect of aluminum coating for preventing steel matrix from corrosion in the corrosive medium was investigated. The static and dynamic corrosion rates were calculated by weight loss test. The corrosion mechanism was discussed. The surface morphology of aluminum coatings before and after corrosion was observed with scanning electron microscope, and the porosity of coating was measured. The results show that the dynamic corrosion rate was twice of the static corrosion rate for the aluminum coating in the corrosion medium containing 5 percent of NaCl solution, when the temperature was (50±1)℃ and the flow velocity of medium was one meter per second. As the exposed area of the steel matrix increased, the cathode depolarization process and the corrosion velocity were raised, and the protection lifetime of aluminum coating decreased. The self-cure of the oxide film and the white rust deposited on the surface of coating can impede aluminum as anode to prevent coating from corrosion. The existence of pores in the coating may weaken the corrosion resistance of the coating gradually in the course of corrosion.
出处
《石油大学学报（自然科学版）》
CSCD
北大核心
2004年第3期72-74,共3页
Journal of the University of Petroleum,China(Edition of Natural Science)
关键词
电弧喷涂工艺
防腐技术
铝涂层
耐蚀性能
失重法
腐蚀介质
arc spraying technique
aluminum coating
corrosive medium
corrosion resistance
weigh loss test
