Ni-Cu-P化学镀层的制备及其耐烟气冷凝液的腐蚀性能

Preparation of Electroless Ni-Cu-P Coating and Its Anticorrosion Behavior in Flue Gas Condensate

为了解决冷凝式燃气利用设备的腐蚀问题,采用化学镀工艺在紫铜基体上沉积Ni-Cu-P层。利用扫描电镜(SEM)、电子能谱(EDX)、电子探针(EPMA)分析镀层的形貌和成分,利用极化曲线和交流阻抗谱考察了紫铜基材及其Ni-Cu-P镀层在15℃和60℃煤气烟气冷凝液中的耐腐蚀性能。结果表明:Ni-Cu-P化学镀层表面均匀平滑,Ni和P元素分布均匀,并均匀沉积有少量Cu元素;在15℃烟气冷凝液中,紫铜基材和镀层的自腐蚀电位、自腐蚀电流密度接近,阻抗值差异不大,耐蚀性相当;在60℃烟气冷凝液中,Ni-Cu-P镀层的自腐蚀电位比紫铜基材的低,自腐蚀电流密度远小于紫铜基材,阻抗值远大于紫铜基材,耐腐蚀性能更好,更适合用作烟气冷凝器冷凝表面的耐腐蚀材料。

Ni-Cu-P coating was prepared on copper substrate by electroless plating.The morphology and composition of resultant coating were analyzed using a scanning electron microscope,an energy dispersive spectrometer and an electron probe micro-analyzer.The anticorrosion behavior of the coating in gas condensate of 15 ℃ and 60 ℃ was evaluated by measuring the polarization curve and electrochemical impedance spectrum.Results indicate that as-deposited coating is uniform and smooth,containing evenly distributed Ni and P and a small amount of Cu.In the gas condensate of 15 ℃,the coating and Cu substrate had similar corrosion potential,corrosion current density and impedance,indicating that they had similar corrosion resistance.In the gas condensate of 60 ℃,the coating had much lower corrosion potential and current density as well as much higher impedance than the Cu substrate,showing significantly increased corrosion resistance.The electroless Ni-Cu-P coating showed promising application as an anticorrosion material of gas condensation exchanger.