稀土铈转化膜在高氯离子溶液中的缓蚀作用

Corrosion-Inhibition Action of Cerium Conversion Coating for Mild Steel in Chloride Solution

添加剂对稀土铈转化膜质量和耐蚀性有较大的影响。通过失重悬挂法研究了不同添加剂(双氧水、氯化钠和苯甲酸纳)对稀土铈转化膜形成的影响规律,即稀土铈转化膜在高氯离子的环境下的缓蚀作用。结果表明,未加添加剂的情况下,随着硝酸铈浓度的增大,铈转化膜厚度逐渐增加,腐蚀速度逐渐降低,耐蚀性逐渐增强,硝酸铈浓度超过0.003mol/L后,腐蚀速度基本保持不变。添加双氧水对稀土铈转化膜的成膜质量没有起到促进作用;一定量氯化钠的加入可以提高转化膜的成膜质量;苯甲酸钠的加入可较大程度地提高稀土铈转化膜的成膜质量,在相同的硝酸铈浓度条件下,添加剂的加入对转化膜厚度的影响不明显。

With a view to the important effects of additives on the quality and corrosion resistance of cerium conversion coating, the corrosion behavior of cerium conversion coating in a Cl^- containing solution was investigated using weight loss method. The effects of the additives such as hydrogen peroxide, sodium chloride, and sodium benzoate were studied. The results showed that in the absence of the additives, the thickness and corrosion resistance of the cerium conversion coating gradually increased with increasing concentration of Ce(NO_3)_3, while the corrosion rate of the cerium conversion coating gradually decreased therewith and kept almost unchanged at a concentration of Ce(NO_3)_3 above 0.003 mol/L. Hydrogen peroxide had no effect on the quality of the cerium conversion coating. Sodium chloride was able to improve the quality of the conversion coating, while sodium benzoate was the most effective in terms of the ability to improve the quality of the cerium conversion coating. Moreover, the additives had little effect on the coating thickness under the same Ce(NO_3)_3 concentration.