中文摘要：

通过电化学阻抗谱（EIS）和极化曲线测量，研究了pH值对热镀锌汽车板和IF钢（无间隙原子钢）基板在5％NaCl溶液中电化学腐蚀行为的影响。结果表明：在三种不同pH值的溶液中，镀锌板的腐蚀过程主要受电荷传递过程控制，而基板的腐蚀过程受氧和氢离子的扩散过程控制。虽然镀锌板的腐蚀速度比基板的腐蚀速度快，但腐蚀过程都呈现了相似的变化趋势，都是随着pH值的增大，电荷转移电阻逐渐增大，腐蚀电流密度依次减小，即腐蚀速度依次减小。

英文摘要：

Electrochemical behaviors of the hot-dip galvanized auto steel sheet and IF （interstitial-free） substrate were investigated by means of EIS and polarization curves in NaC1 solutions with various pH values. The results showed that the corrosion process of the galvanized steel sheet was mainly controlled by charge transfer process, but corrosion of the IF substrate was controlled by the diffusion process of oxygen and hydrogen ions in the solutions. The galvanized steel presented a higher corrosion rate than the IF steel substrate, but the corrosion evolution tendencies were similar. With increasing the pH value the charge transfer resistance increased, and thus the corrosion current density decreased, i. e. , the corrosion rate decreased gradually.