含铜低碳钢在不同pH值的Cl^(-)环境中的腐蚀性能研究

Corrosion Performance of Low Carbon Steels Containing Copper in Cl^(-)Environment with Different pH Values

为探究含铜低碳钢在不同pH值条件下的腐蚀规律,采用电化学工作站和金相显微镜对不同pH值的NaCl环境中的普通耐候钢(Q345)、含铜低碳钢(0Cu3Cr)和船体含铜低碳钢(0CuAl)的极化曲线、交流阻抗谱和微观形貌进行分析,观察在不同pH值的NaCl环境中的含铜钢与低碳钢的腐蚀性能差异。结果表明:在NaCl环境中,pH=12时3种试样的自腐蚀电位较高,0Cu3Cr和0CuAl的腐蚀过程受阳极溶解反应控制,而Q345受阴极反应控制,Q345和0Cu3Cr在pH=6时的自腐蚀电位略大于pH=8时的;3种试样在pH=12的NaCl环境中的电荷转移电阻值最大;pH=6时0Cu3Cr表面的点蚀坑较小且数量较少,pH=8时表面点蚀坑较大且数量较多;0CuAl在pH=8时的耐蚀性比pH=6时的好。

For exploring the corrosion rules of copper-containing low carbon steel under different pH conditions,the electrochemical workstation and metallographic microscope were used to analyze the polarization curves,AC impedance spectra and micro morphologies of ordinary weathering steel(Q345),copper-containing low carbon steel(0Cu3Cr)and hull copper-containing low carbon steel(0CuAl)in NaCl environments with different pH values.Additionally,the difference in corrosion performance between copper-containing steel and low carbon steel in NaCl environments with different pH values was observed.Results showed the self-corrosion potential of the three samples was higher in the NaCl environment with pH=12.The corrosion processes of 0Cu3Cr and 0CuAl were controlled by the anodic dissolution reaction,while that of Q345 was controlled by the cathodic reaction.Moreover,the self-corrosion potential of Q345 and 0Cu3Cr at pH=6 was slightly greater than that at pH=8.The charge transfer resistance values of the three kinds of samples were the largest in the NaCl environment with pH=12.When pH=6,the pitting pits on the surface of 0Cu3Cr were smaller and less numerous.When pH=8,the pitting pits on the surface were larger and more numerous.Besides,the corrosion resistance of 0CuAl at pH=8 was better than that at pH=6.