通过在不同氧含量环境中对汽车热镀锌板进行泥浆附着试验,采用扫描电镜、X射线光电子谱和拉曼光谱等手段,研究在间歇通O2和通N2情况下汽车用镀锌板的腐蚀行为。结果表明:在间歇通O2的情况下,锌层大部分被腐蚀,而且在基体上有一些红锈和黑锈产生,镀锌板表面的腐蚀产物呈现着不均匀的针状物;而在间歇通N2时,镀锌板的锌层脱落面积较少,基体上没有产生红锈,腐蚀产物呈大块状;在间歇通O2和通N2的情况下,镀锌板的腐蚀速率先增后降,在200h时,前者的腐蚀质量损失速率是后者的2倍左右:镀锌板附着库尔勒泥浆时的腐蚀过程受氧去极化过程控制。
In environments of different oxygen contents, the corrosion behaviors of hot-dip galvanized (HDG) steel sheet used in automobile under mud adhesion were investigated by scanning electronic microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The results show that the zinc coating is eroded mostly, and some red rust and black rust appear on the substrate in the environment of oxygen supplied intermittently. The corrosion products on the galvanized steel sheet are needle-like objects. While in the environment of nitrogen supplied intermittently, a little area of the zinc coating is erode, and no red rust appears on the substrate. Corrosion products form on the blocks. With time prolongs, the corrosion rates of mass loss increase firstly whereas then decrease, and the corrosion rate of mass loss with oxygen supply is about two times greater than that with nitrogen supply under the mud adhesion up to 200 h. The corrosion processes of the galvanized steel sheet under alkaline mud adhesion are controlled by oxygen depolarization reactions.