铜合金在海水环境中的腐蚀规律及主要影响因素

CORROSION OF COPPER ALLOYS IN NATURAL SEAWATER AND MAIN INFLUENCE FACTORS

铜合金在海洋环境中以均匀腐蚀为主，其中以全浸最重、潮差次之、飞溅最轻。随暴露时间的增加，平均腐蚀速度降低。在泥沙冲击腐蚀条件下，多数铜合金腐蚀速度增大。ＨＡｌ７７－２Ａ板在全浸和潮差区显示出最优的耐蚀性。半硬态ＱＳｎ６．５－０．１合金板材在全浸区的腐蚀速度较低，特别是对泥沙冲击腐蚀不敏感。随着暴露时间增加，抗海洋生物附着能力亦降低，死亡海洋生物腐烂产生的硫化物引起严重局部腐蚀。双相黄铜腐蚀速度高于单相黄铜。ＢＦｅ３０－１－１管组织不均匀导致晶间腐蚀。由于残余应力影响，管材腐蚀速度大于板材。多数铜合金腐蚀速度与时间关系服从幂函数规律。

Copper alloys were mainly of uniform corrosion in natural seawater, and they were corroded most seriously in immersion, second in tide immersion and least in splash. With the increase of exposure time, the average corrosion rate decreased; and it increased under the erosion corrosion of silt. With the increase of temperature of seawater, the corrosion rates of most of copper alloys increased, however they decreased in the tide immersion and splash. The sensitivity of temperature of all the alloys decreased with the increase of exposure. The plate QSn6.5-0.1 in half hard state showed low corrosion rates in immersion, but it was not sensitive to the erosion of silt. The biofouling resistance of all the alloys decreased with the increase of exposure time. The rot of dead marine living beings produced sulphides and so that it caused serious local corrosion. The corrosion rates of dual phase brass were higher than that of single phase brass, and inhomogeneous microstructure of BFe30-1-1 tubes resulted in intergranular corrosion. For the influence of residual stress, the corrosion of tubes was higher than that of plates. The relation of corrosion rates with exposure time of most of copper alloys complied with the law of power function.