电厂不锈钢换热管化学镀Ni-Co-P合金镀层及其耐点蚀性能

采用优化的化学镀液配方和工艺条件,在不锈钢管外表面制备了非晶态的化学镀Ni-Co-P合金镀层。通过浸泡腐蚀试验和电化学腐蚀试验,比较了不锈钢管和化学镀Ni-Co-P管的耐点蚀性能。结果表明:在5.0%的盐酸溶液和酸性氯化钠溶液中,化学镀Ni-Co-P管的平均腐蚀速率明显低于不锈钢管的平均腐蚀速率;在3.5%的氯化钠溶液中,化学镀Ni-Co-P合金镀层的电荷转移电阻较大(约为2.13×10^4Ω·cm^2),较不锈钢表现出更好的耐点蚀性能。

Electroless Plating of Ni-Co-P Alloy Coating on Stainless Steel Heat Exchange Tube Used in Power Plant and Its Pitting Corrosion Resistance

An amorphous electroless Ni-Co-P alloy coating was prepared on the external surface of stainless steel tube with the optimized solution formulation and process conditions.The pitting corrosion resistance of stainless steel tube and electroless-plated Ni-Co-P tube was investigated through immersion corrosion test and electrochemical corrosion test.The results showed that the average corrosion rate of electroless-plated Ni-Co-P tube was obviously lower than that of stainless steel tube in 5%hydrochloric acid and acid sodium chloride solution.In 3.5%sodium chloride solution,electroless Ni-Co-P alloy coating showed a larger charge-transfer resistance of about 2.13×10^4Ω·cm^2,indicating that the pitting corrosion resistance of electroless Ni-Co-P alloy coating was better than that of stainless steel.