304不锈钢在人工海水环境中的腐蚀磨损行为研究

目的阐述304不锈钢在人工海水环境中的腐蚀磨损行为及其力-电化学耦合作用下的损伤机理,为海水服役环境中海洋装备的开发和利用提供理论支持。方法利用腐蚀磨损试验仪研究了304不锈钢在人工海水环境中的摩擦学性能和电化学性能及其交互作用下的腐蚀磨损行为,并利用扫描电镜、X射线衍射仪、激光共聚焦显微镜等仪器对磨痕表面进行表征与分析。结果在载荷作用下,304不锈钢的腐蚀电位从静态腐蚀的-0.310V变为-0.368V,腐蚀电流密度也增加了约1个数量级。阳极恒电位下,304不锈钢和Al_2O_3陶瓷球摩擦副的摩擦系数比阴极保护下的小。载荷为5N时,304不锈钢的腐蚀磨损率为0.195mm~3/d,其中,腐蚀加速磨损速率占68.7%;载荷为15N时,总磨损速率明显增加,其中,纯磨损率所占比例最大,为60.1%,此时腐蚀加速磨损速率占比为39.1%。结论 304不锈钢的腐蚀磨损行为是"机械去钝化-化学再钝化"的动态过程。腐蚀和磨损过程存在明显的交互作用。在磨损过程中,304不锈钢表面发生马氏体相变,通过电偶腐蚀进一步加强腐蚀作用;同时,腐蚀过程的反应产物使304不锈钢的耐磨性能下降。随着载荷的增加,对总腐蚀磨损速率贡献最大的由腐蚀加速磨损速率逐渐变为纯磨损率,载荷对304不锈钢的机械磨损影响更大。

Tribocorrosion Behaviors of 304 Stainless Steel in Artificial Seawater

The work aims to illustrate the tribocorrosion behavior of 304 stainless steel in artificial seawater and the damage mechanism under mechano-electrochemical coupling, so as to provide theoretical support for development and utilization of marine equipment in the marine service environment. The tribological properties and electrochemical properties as well as the tribocorrosion behaviors of 304 stainless steel in artificial seawater were studied by tribocorrosion tester. The worn surface was characterized and analyzed by scanning electron microscopy, X-Ray diffraction and laser scanning confocal microscopy. Under load, the corrosion potential of 304 stainless steel changed from -0.310 V to -0.368 V at static corrosion; and the corrosion current density also increased by almost an order of magnitude. The friction coefficient of the 304 stainless steel and Al2O3 ceramic ball friction pair at the anode constant potential was smaller than that at the cathodic protection. When the load was 5 N, the corrosion wear rate of 304 stainless steel was 0.195 mm3/d, among which, the accelerated wear rate of corrosion accounted for 68.7%. When the load was 15 N, the total wear rate increased obviously, and the pure wear rate accounted for the largest proportion, namely 60.1% and the corrosion accelerated wear rate accounted for 39.1%. The corrosion wear behavior of 304 stainless steel is a dynamic process of "mechanical depassivation - chemical repassivation". There is a clear interaction between the corrosion and wear processes. During the wear process, martensite transformation occurs on the surface of 304 stainless steel, and the corrosion is further strengthened by galvanic corrosion. At the same time, the reaction product of the corrosion process reduces the wear resistance of 304 stainless steel. As the load increases, the corrosion accelerated wear rate that contributes the most to the total corrosion wear rate gradually changes to the pure wear rate, and the load has a greater influence on the mechanical wear of 304 stainless steel.