摘要
通过动态FeSO_(4)溶液冲刷在70Cu-30Ni合金管内壁形成稳定的FeSO_(4)预成膜层,并通过不同速率的动态海水冲刷试验,研究预成膜层的耐海水冲刷腐蚀行为。FeSO_(4)预成膜实验结果显示,在200 mg/L FeSO_(4)溶液0.5 m/s流速下经历4 d冲刷,70Cu-30Ni合金管内壁形成一层淡黄色金属光泽膜层,随着时间增加,膜层颜色加深,厚度增加;30 d时,会形成底层NiO-Ni(OH)_(2)层,中间层Cu_(2)O-FeOOH致密层和表层Fe_(2)O_(3)-FeOOH疏松层的复合膜层。3个月周期的动态海水冲刷腐蚀试验结果显示,经历动态海水冲刷后,0.5和1.5 m/s低冲刷流速下试样的预成膜层保存较完整,仅出现轻微疏松层减薄现象;2.5 m/s高冲刷流速条件下,预成膜膜层局部位置存在疏松层剥离现象。XPS分析显示,高冲刷流速下,耐蚀膜层中Ni含量略有增加,Cu_(2)O在Cu组分中的含量增加,FeOOH含量在Fe组分中增加。电化学测试显示,随着冲刷流速的增加,预成膜层的电荷传递阻抗逐渐减小,由0.5 m/s状态下的2.28×10^(5)Ω·cm^(2),减小到2.5 m/s时的6.51×10^(4)Ω·cm^(2)。70Cu-30Ni合金管FeSO_(4)预成膜层组成为NiO-Ni(OH)_(2)/Cu_(2)O-FeOOH/Fe_(2)O_(3);随着冲刷速率的增加,合金管局部腐蚀现象更加显著。
A pre-chemical conversion film on the inner walls of 70Cu-30Ni alloy pipeline was first prepared with a flowing FeSO_(4)solution,and then of which the erosion corrosion behavior in flowing seawater of various speeds was investigated by means of seawater circulation loop.The result showed that a chemical conversion film is obtained during the immersing-and flushing-process of the 200 mg/L FeSO_(4)solution in conditions:flowing speed 0.5 m/s,pH 6.0,at 25°C for 30 d,which is a composite film composed of an inner layer of NiO-Ni(OH)_(2),a compact middle layer of Cu_(2)O-FeOOH and a loose outer layer of Fe_(2)O_(3)-FeOOH.Long-term seawater erosion corrosion test results showed that being suffered from flowing sea water of 0.5 and 1.5 m/s,the chemical conversion film covered pipe lines display relative sound anticorrosion performance with only slightly thinning of the top loose layer of the film,while with the increasing seawater flowing rate up to 2.5 m/s the loose layer on top of the conversion film is significantly thinned with locally spalling off,thus exposing the compact middle layer underneath.XPS analysis results showed that the chemical conversion films had been suffered from erosion corrosion of high-speed flowing seawater display higher amount of Ni,Cu_(2)O and FeOOH on the conversion film surface.Electrochemical impedance results showed that the charge transfer resistances of the chemical conversion films varied in the following descending order:from 2.28×10^(5)Ω·cm^(2),8.77×10^(4)Ω·cm^(2) to 6.51×10^(4)Ω·cm^(2),after being subjected to erosion-corrosion test by seawater of flowing speeds of 0.5,1.5 to 2.5 m/s,respectively.
作者
杨新宇
李祯
段体岗
黄国胜
马力
刘峰
姜丹
YANG Xinyu;LI Zhen;DUAN Tigang;HUANG Guosheng;MA Li;LIU Feng;JIANG Dan(State Key Laboratory for Marine Corrosion and Protection,Luoyang Ship Material Research Institute,Qingdao 266237,China;College of Material Science and Chemical Engineering,Harbin Engineering University,Harbin 150001,China)
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2023年第3期561-568,共8页
Journal of Chinese Society For Corrosion and Protection
