电弧喷涂铝涂层海洋飞溅区腐蚀模拟试验研究

采用自制的海洋飞溅区腐蚀模拟试验装置,对电弧喷涂铝涂层在海洋飞溅区的腐蚀行为进行了研究。结果表明:在海洋飞溅区模拟条件下,涂层试样和基体试样的腐蚀失重与试验时间的关系曲线遵循幂函数规律。试验初期,涂层腐蚀较轻微;试验中期,涂层在闭塞电池作用下发生坑蚀,由于铝涂层的自腐蚀电位远比20号钢基体低,腐蚀坑不向纵深方向发展,而是朝横向扩展,涂层作为牺牲阳极保护基体免受腐蚀;随着涂层的不断消耗,涂层表面出现锈迹,但是涂层对基体金属仍具有一定的保护作用。

Corrosion Behavior of Aluminum Coating by Arc Spraying in Simulated Marine Splash Zone

Corrosion behavior of aluminum coating by arc spraying in marine splash zone was studied on a simulation apparatus. Results showed that the relationship between weight loss of coating sample, substrate sample and exposure time obeyed with power function in the simulated conditions of the marine splash zone. In the initial stage,the corrosion on aluminum coating was slight. In the middle stage, pitting corrosion occurred on aluminum coating because of the occluded cell effect. However, as compared with 20# steel （ substrate material ）, aluminum coating had a lower free corrosion potential. Therefore, these corrosion pits grew wider, but not deeper, and aluminum coating acting as a sacrificial anode protected the subotrate material against corrosion. With the depleting of aluminum coating, a few rusty stains appeared on aluminum coating. The prepared coating exhibited obvious protection for the substrate.