锆对20碳钢在锌合金液中腐蚀行为的影响

Effect of zirconium on corrosion behavior of carbon steel in molten zinc alloy

在20碳钢和Zn-6%Al-3%Mg合金液中分别添加0.6%Zr,用扫描电镜和X射线衍射仪研究了锆元素对20碳钢在Zn-6%Al-3%Mg锌合金液中腐蚀行为的影响。结果表明:20碳钢在510℃的Zn-6%Al-3%Mg和Zn-6%Al-3%Mg-0.6%Zr合金液中的腐蚀程度都随侵蚀时间的增加而增大,但是20碳钢在Zn-6%Al-3%Mg-0.6%Zr合金液中的腐蚀程度明显减轻。随着侵蚀温度的升高,20碳钢在Zn-6%Al-3%Mg-0.6%Zr合金液中的腐蚀深度由缓慢增加转为急剧增大,为减少Zn-6%Al-3%Mg-0.6%Zr合金液对碳钢的腐蚀程度,热浸镀锌温度应低于510℃。含0.6%Zr的20碳钢在Zn-6%Al-3%Mg合金液中经过长时间侵蚀后,可形成较厚的致密Fe-Al化合物层,使含锆20碳钢的腐蚀速率明显低于20碳钢,因此在钢中添加0.6%的锆元素可提高钢制锌锅的使用寿命。

0.6%Zr was added to 20 carbon steel and molten Zn-6%Al-3%Mg alloy respectively. The effect of zirconium on corrosion behavior of the 20 carbon steel in molten Zn-6%Al-3%Mg zinc alloy was studied by means of scanning electron microscopy(SEM) and X-ray diffractometer(XRD). The results show that the corrosion degree of the 20 carbon steel in molten Zn-6%Al-3%Mg and Zn-6%Al-3%Mg-0.6%Zr alloys at 510 ℃ increases with the increase of corrosion time. However, the corrosion of the 20 carbon steel in molten Zn-6%Al-3%Mg-0.6%Zr alloy is obviously reduced. With the increase of corrosion temperature, the corrosion depth of the 20 carbon steel in molten Zn-6%Al-3%Mg-0.6%Zr alloy increases slowly at first and then increases sharply. In order to reduce the corrosion degree of carbon steel in the molten Zn-6%Al-3%Mg-0.6%Zr alloy, the hot-dip galvanizing temperature should be lower than 510 ℃. The 20 carbon steel containing 0.6%Zr can form a thick dense Fe-Al compound layer after long time erosion in molten Zn-6%Al-3%Mg alloy, and the corrosion rate of the 20 carbon steel containing 0.6%Zr is obviously lower than that of 20 carbon steel without Zr. Therefore, adding 0.6% zirconium to the 20 carbon steel can improve the service life of steel zinc pot.