高铁散热器用3003铝合金焊接隔板的腐蚀机理研究

Corrosion Behavior of Welded Partitions of 3003 Al-alloy Used for Radiators of High-speed Train

采用X射线荧光光谱(XRF)、扫描电镜(SEM)、电化学阻抗谱(EIS)和极化曲线分析了实际环境中的沉积粉尘对高铁散热器用3003铝合金焊接隔板腐蚀行为的影响机理,并建立了铝合金焊接隔板的腐蚀深度预测模型。结果表明,在粉尘溶液环境中,铝合金焊接隔板在腐蚀初期以点蚀为主,随后演变为沿晶腐蚀。铝合金焊接隔板的主要腐蚀产物为Al(OH)_(3)和AlCl_(3)。铝合金焊接隔板经粉尘溶液全浸180 d后,腐蚀电位下降了24.5%,腐蚀电流密度提高了156.7%。结合全浸实验和实际服役8 a的构件腐蚀深度测试结果,建立了高铁散热器用铝合金焊接隔板最大腐蚀深度预测模型。

The corrosion behavior of welded partitions of 3003 Al-alloy,used for radiators of highspeed train,in artificial solution of settling dust,which aims to simulate the synergistic ation of the settling dusts and rains on the partitions in the real service,was studied by means of immersion test,polarization curve measurement,X-ray fluorescence(XRF),scanning electron microscopy(SEM),and electrochemical impedance spectroscopy(EIS).Meanwhile,the relevant prediction model for the corrosion depth of welded partitions was established.The results show that,the pitting corrosion is dominant at the initial stage of corrosion,and then gradually evolves into intergranular corrosion.The main corrosion products of welded partitions are Al(OH)_(3)and AlCl3.In comparison with those of the as received ones,the corrosion potential of welded partitions after immersion for 180 d decreases by 24.5%and the corrosion current density increases by 156.7%.A prediction model for the maximum corrosion depth of welded partitions was established based on data of the immersion test results and the measured corrosion depth of the very welded partitions after 8 a of live vehicle service.