研究了臭氧存在下,在磷化液中添加Ni^2+改善磷化膜耐蚀性能的情况。结果表明,在臭氧浓度为1.62mg/L、Ni^2+为0.8 g/L、pH值为2.75的磷化液中,40℃处理5 min获得的磷化膜膜层致密,呈暗灰色,膜重为6.19g/m2,耐硫酸铜点蚀时间大于109 s;增加Ni^2+到1.6 g/L,膜重略减小,耐蚀时间增大到127 s。扫描电镜观察发现,臭氧浓度在1.62 mg/L时磷化膜由较大的厚板状晶粒构成,紧贴基体覆盖严密。由XRD结果可知,有臭氧时,磷化膜的主要物质是Zn3(PO4)2.4 H2O,并有Zn2Fe(PO4)2.4 H2O;当臭氧浓度为1.62 mg/L时,Fe(110)面的强度最小,说明磷化膜将碳钢基体表面覆盖严密。电化学测试表明磷化膜耐蚀性良好。
The corrosion resistance of phosphated film obtained in the phosphating solution with ozone and Ni^2+ was investigated.The results indicated that the film obtained from the phosphating solution with 1.62 mg/L dissolved ozone,0.8 g/L Ni^2+,pH 2.75,at 40 ℃ for 5 min was dull-grey and dense,the weight of the film reached 6.19 g/m^2,and the time of dropping corrosion resistance of CuSO4 was more than 109 s;increasing Ni^2+ concentration to 1.6 g/L,the film weight was little decreased,and the dropping time increased to 127 s.The SEM showed that the coating was composed of biggish slab-like crystal grains and covered compactly on the substrate while ozone was 1.62 mg/L.The XRD showed that the main composition of the coating was Zn3(PO4)2·4H2O and Zn2Fe(PO4)2·4H2O with ozone existing;when ozone was 1.62 mg/L,the intension of plate Fe(110) was minimal which indicated that the surface of the carbon steel had been covered by phosphate coating narrowly.The electrochemical testing showed the film had good corrosion resistance.