西沙海洋大气环境中典型材料腐蚀形貌识别

目的获得西沙海洋大气环境中典型材料的表面腐蚀形貌参数,分析其腐蚀规律。方法采用室外大气暴露试验,研究5052铝合金、304不锈钢和EH36低合金钢在西沙海洋大气环境中的腐蚀形貌及腐蚀规律,并采用图像数字处理方法识别试样表面腐蚀特征。结果 EH36钢的大气腐蚀形貌以均匀腐蚀和腐蚀坑为主,而5052铝合金以及304不锈钢以点蚀为主,EH36低合金钢的腐蚀速率明显高于5052铝合金和304不锈钢。三种典型材料腐蚀面积百分比与腐蚀坑面积百分比的变化趋势相同,5052铝合金和EH36低合金钢的腐蚀面积百分比和腐蚀坑面积百分比与二者腐蚀速率变化规律一致,而304不锈钢的腐蚀面积百分比和腐蚀坑面积百分比与其腐蚀速率变化规律相反。5052铝合金和EH36低合金钢1年周期试样的腐蚀坑数目均大于2年周期试样,而对于304不锈钢,1年周期试样的腐蚀坑数目与2年周期试样差别不大。结论西沙大气环境中,三种典型材料的腐蚀速率、腐蚀面积百分比、腐蚀坑面积百分比均有明显不同,对同一种材料,其正面的腐蚀面积百分比、腐蚀坑面积百分比、腐蚀坑数与背面也有较大差别。

Corrosion Morphology Identification of Typical Materials in Xisha Marine Atmospheric Environment

Objective To obtain the surface corrosion morphology parameters of typical materials in Xisha marine atmospheric environment, and analyze the corrosion regularities. Methods The corrosion morphology and corrosion law of 5052 aluminum al-loy, 304 stainless steel and EH36 low alloy steel in Xisha marine atmospheric environment were studied through outdoor exposure tests. The digital image processing method was used to analyze the corrosion characteristics of the sample surface. Results The atmospheric corrosion morphology of EH36 steel was mainly uniform corrosion and corrosion pits; while that of 5052 aluminum alloy and 304 stainless steel was mainly pitting corrosion. The corrosion rate of EH36 low alloy steel was significantly higher than that of 5052 aluminum alloy and 304 stainless steel. The change regularity of the percentage of corrosion area of these three typical materials was the same as the change regularity of the percentage of pits area. The change regularity of the percentage of corrosion area and the percentage of pits area of 5052 aluminum alloy and EH36 low alloy steel were consistent with the change of their cor-rosion rate; while the percentage of corrosion area and the percentage of pits area of 304 stainless steel were opposite to the change of its corrosion rate. For 5052 aluminum alloy and EH36 low alloy steel, the number of corrosion pits of the one-year period specimen was greater than that of the two-year period specimen. For 304 stainless steel, the number of corrosion pits of the one-year period specimen was not much different from that of the two-year period specimen. Conclusion The corrosion rate, cor-rosion area percentage, and percentage of pits area of these three typical materials in Xisha atmospheric environment are all signifi-cantly different. For the same material, the percentage of corrosion area, the percentage of pits area and the number of pits on the front side are quite different from those on the back side of the specimen.