海洋大气环境下17-7PH不锈钢的接触腐蚀研究

 为了研究17-7PH不锈钢在海洋大气环境下接触腐蚀的防护问题，将不同表面状态的17-7PH不锈钢板状试样在青岛团岛和海南万宁进行1年的大气暴晒试验，对其宏观腐蚀形貌对比，并测定其疲劳寿命，采用扫描电子显微镜(SEM)观察暴晒试样表面腐蚀形貌，用光学显微镜比较腐蚀坑深度，分析海洋大气腐蚀对17-7PH不锈钢疲劳性能的影响，最后得出了17-7PH不锈钢的腐蚀防护措施。结果表明：在青岛暴晒的不涂漆17-7PH不锈钢试样表面色泽变暗，有均匀的细小点蚀，而海南的试样表面有大面积较均匀的褐色锈层，特别是17-7PH不锈钢与TC18钛合金连接处腐蚀较为集中，但腐蚀并没有降低其疲劳寿命；从暴晒试样的表面微观腐蚀形貌比较，无论涂漆与否，17-7PH不锈钢表面都有轻微腐蚀，但只局限于表层，点蚀不深，并且趋向均匀腐蚀；17-7PH不锈钢抗大气腐蚀性能很好，经钝化后可不涂漆直接在海洋大气环境中使用1年，而不会对其疲劳性能产生明显影响。

Research on Galvanic Corrosion of 17-7PH Stainless Steel in Marine Atmosphere

In order to research the protective problems of contact corrosion about 17-7PH stainless steel in the marine atmosphere environment, atmospheric exposure test of 17-7PH stainless steel plates with different surface condition were investigated at Tuandao of Qingdao and Wanning of Hainan for 1 year. Then, comparing macro corrosion morphology of samples, testing fatigue lives, observing surface corrosion morphology of exposed samples by scanning electron microscope (SEM) and corrosion depth of the pit by optical microscope, the effect of the marine atmospheric corrosion on fatigue performance of 17-7PH stainless steel was analyzed. Finally, the corrosion protection measures of 17-7PH stainless steel were obtained. The results indicate that the surface colour of 17-7PH stainless steel samples with no paint exposed in Qingdao become darker and samples′ surface have even small pitting corrosion, while surface of samples exposed in Hainan have brown rusty layer which is relatively even and large area, especially on connection of 17-7PH stainless steel and TC18 titanium alloy. However, corrosion does not reduce their fatigue lives. In comparison with the microscopic corrosion morphology of exposed samples, whether painted or not, there are mild corrosion on 17-7PH stainless steel surface, but only limited in the surface layer. Pitting corrosion is not deep, and inclines to uniform corrosion. 17-7PH stainless steel has good atmospheric corrosion resistance performance, and passivated stainless steel with no paint can be directly used in the marine atmosphere environment for 1 year, which has no influence on fatigue property.