流动和污染海水诱发并加速铜合金脱成分腐蚀的研究

分析了研究了4种铜合金在舟山、青岛、榆林各海水腐蚀试验站暴露4年以上的腐蚀数据，得到流动海水和污染海水对铜合金脱成分腐蚀的基本规律和机理，双相黄铜及硅青铜对流动海水的腐蚀最为敏感，从前者的脱成分腐蚀机理出发，提出了流动诱发和加速铜合金脱成分腐蚀的新概念。其关键在于，随着原始表现膜的腐蚀消耗，不能形成新的致密的耐冲击的腐蚀产物膜，使合金元素向表在贩扩散过程得不到抑制，从而使双相黄铜的脱成分腐蚀不断被诱发，被加速，其中尤以β相连续的双相铜被加速的趋势最为明显，表面腐蚀产物膜分析表明，这两类铜合 腐蚀产物膜具备致密和耐冲击腐蚀的特征，在污染海水的情况下，由于硫离子等的作用，同时不能形成致密的腐蚀产物膜，同样使双相黄铜的腐蚀被逐年加速，由于这种污染元素的作用在试样露出水面时依然存在，致使潮差暴露也出现类似情况。

Study on Dealloying Corrosion of Cu alloys Induced and Accelerated by Flowing or Polluted Seawater

The corrosion data of 4 copper alloys exposed to seawater of Zhoushan,Qingdao,Yulin experiment network for 4 years were studied. From the result the basic rule and new mechanisms of severe dealloying corrosion of copper alloys both in flowing and polluted seawater were obtained respectively. Among the 9 copper alloys, brass with double phase and silicon bronze are the most sensitive ones to corrosion of flowing seawater,i.e.the most severe corrosion of the two alloys happened in zhoushan. From this phenomenon and the observation of corrosion product film,a new concept was proposed that flowing seawater induced and accelerated the dealloying corrosion of copper alloys. The key point of the new concept is weather a compact and inpact resistant corrosion film could be formed so as to inhibit the diffusion of the alloying element toward the surface or not, as the specimens exposed to seawater. It is due to the character of the product film formed on them when exposed to seawater. In the case of polluted seawater, because of the existence of S 2- ion etc .,the corrosion product film formed could not be compact and the dealloying corrosion of the double phase brass were accelerated also year by year. For the pollution ions were existed on the specimens when they emerged from seawater, the dealloying corrosion of double phase brass exposed to mean tide zone was also accelerated.