稀土硝酸铈对油管锌钙系磷化膜形貌和性能的影响

Influence of Rare Earth Cerium Nitrate on Morphology and Properties of Zinc-Calcium Phosphating Film on Tubing

以油管常用的材料45#钢作为基体,在添加了稀土硝酸铈的磷化液中制备锌钙系磷化膜。研究了硝酸铈质量浓度对磷化膜的元素组成、膜重、厚度和耐蚀性的影响。结果表明:硝酸铈不会改变磷化膜的元素组成,但是会改变磷化膜的形貌、膜重和厚度,从而显著影响其耐蚀性。随着硝酸铈质量浓度增加到100 mg/L,磷化膜中Zn和Ca质量分数均先升高后降低,P质量分数基本呈降低的趋势,磷化膜的晶粒形态及晶粒间隙有所不同,膜重先增加后下降,厚度先增加后减薄,与之对应的磷化膜耐蚀性先逐渐提高随后变差。当硝酸铈质量浓度为50 mg/L时,制备的磷化膜晶粒细小、均匀且致密度较高,膜重最高,达到12.45 g/m^2,厚度达到8.1μm,该磷化膜表现出良好的耐蚀性,明显优于其他磷化膜。

The zinc-calcium phosphating film was prepared by adding rare earth cerium nitrate into the phosphating solution using 45#steel as the matrix.And the influence of cerium nitrate mass concentration on the elemental composition,weight,thickness and corrosion resistance of phosphating film was studied.The results showed that cerium nitrate did not change the elemental composition of phosphating film,but it can change the morphology,weight and thickness,thus significantly affecting the corrosion resistance of phosphating film.As the mass concentration of cerium nitrate increased to 100 mg/L,the mass fraction of Zn and Ca in phosphating film first increased and then decreased,while the mass fraction of P showed a trend of decrease.The grain morphology and grain gap of phosphating film were different.The weight and thickness increased first and then decreased,which lead to a gradual improvement in the corrosion resistance followed by deterioration.When the cerium nitrate mass concentration was 50 mg/L,the phosphating film with uniform grain size and high density had the highest weight up to 12.45 g/m2 and thickness up to 8.1μm.The phosphating film showed good corrosion resistance,obviously better than that of the other phosphating film.