三元复合添加剂复配比例对钢铁锌钙系黑磷化的影响

Effect of Ratio of Composite Additives on Zn-Ca System Black Phosphating Process of Iron and Steel

已有的中温锌钙系黑色磷化膜的黑色度、均匀度、附着力及耐蚀性较差,为了克服这些缺点,在中温锌钙系黑磷化液中加入复合添加剂,研究了添加剂复配比例对黑磷化液稳定性以及磷化膜外观质量、耐蚀性、耐磨性的影响,确定了添加剂最佳复配比例,并测试了最佳复配比例时制得的磷化膜的组织结构。结果表明:当4.8g/L柠檬酸三钠、4.0g/LEDTA-2Na和1.6g/L硝基胍三元复配时,磷化液无沉渣,磷化膜表面黑亮光滑,孔隙少,晶粒细致均匀,耐蚀性及耐磨性良好。

Composite additives were introduced into Zn-Ca system black phosphating solution to prepare phosphating coating on the surface of iron and steel. The effects of the ratio of composite additives on the stability of the phosphating solution as well as appearance, corrosion resistance and wear resistance of the phosphating coating were investigated. The optimal ratio of the composite additives was determined, and the microstructure of the phosphating coating was analyzed. Results indicate that the black phosphating solution containing 4.8 g/L sodium citrate, 4.0 g/L EDTA-2Na and 1.6 g/L nitroguanidine is free of sediments, and resultant black phosphating coating composed of fine grains is bright and compact, having good corrosion resistance and wear resistance.