【摘要】 该文研究了热电站冷凝器用黄铜管的腐蚀特征,发现腐蚀在铜管内表面大量发生,腐蚀孔分布广,具有点腐蚀针孔特征。腐蚀表面有较多的脱落晶粒,腐蚀前沿总是在晶界处扩展,腐蚀表现为晶粒沿晶界的剥落,腐蚀孔的边缘具有流体冲刷的痕迹。研究认为引起冷凝器用黄铜管腐蚀的3种主要机制分别是由内表面膜和铜管材料之间的电位差引起的电化学点腐蚀、黄铜的脱锌腐蚀以及水流的冲刷腐蚀,其中电化学点腐蚀是铜管发生早期穿孔破坏的主要原因。更多还原

【Abstract】 The corrosion characteristics and mechanisms of brass tubes for power plants are studied.It is found that corrosion occurs extensively on the inner surface of the tube.Corrosion holes are distributed widely and with characteristics of pin holes.Many grains have come off from the inner sufaces of the tube and the foretips of the corrosion keep expanding along the grain boundaries.It is shown that the corrosion appears to be the coming off of grains along the grain boundaries and there are marks of fluid rushing on the borders of corrosion holes.Based on the observation of the microstructure of corrosion,it is concluded that there are three different corrosions in the tube,i.e.electrochemical corrosion caused by the electric voltage between the inner surface film and substrate of the tubes,zinc loss corrosion and fluid rushing corrosion with electrochemical corrosion being the main cause for the corrosion holes in the tubes.更多还原