新型磷化液的研制

采用正交试验法优选了磷化液最佳配方为217g/L磷酸,50g/L氧化锌,40g/L磷酸二氢钠,3g/L钼酸铵,2g/L植酸,1.5g/L乙酸锰,4.5g/L氧化促进剂DJ1,1.5g/L低温促进剂DJ2,3g/L复配表面活性剂DJ3。所得磷化膜经金相显微镜观察,其金相结构致密、连续。通过电化学方法测试成膜过程的极化曲线,表明磷化过程成膜后,腐蚀电流基本保持不变。利用X射线光电子能谱测定膜表面的元素组成,发现Zn、Fe、P的不同峰值的能谱,及O的能谱峰及俄歇能谱同时存在,说明磷化膜主要是由Fe、Zn的多种磷酸盐构成。该磷化液稳定,沉渣少,成膜速度快,磷化膜耐蚀性能好。

Preparation of novel phosphating solution

The optimal phosphating formula was chosen by orthogonal test as follows: 217 g/L phosphoric acid, 50 g/L zinc oxide, 40 g/L sodium dihydrogen phosphate, 3 g/L ammonium molybdate, 2 g/L phytic acid, 1.5 g/L manganese acetate, 4.5 g/L oxidation accelerator DJ_1, 1.5 g/L low-temperature accelerator DJ_2,3 g/L complex surfactant DJ_3. The obtained phosphating films were examined by metallographic microscope. Their metallographic structure is compact and continuous. The polarization curve during the formation of phosphating film as measured by electrochemical method indicated that the corrosion current is basically unchanged after the film is formed. The chemical composition of phosphating film investigated by X-ray photoelectron spectroscopy (XPS) showed that some obvious peaks of Zn,Fe, and P elements and different spectrographic peaks of O exist simultaneously, and the phosphating film is mainly consisted of several phosphate of Fe and Zn. The phosphating bath is stable, and has less sludge and higher film-forming rate. The phosphating film has good corrosion resis-tance.