AZ91镁合金磷化液配方及优选

Phosphatization Recipe and Technique Optimization of Magnesium Alloy AZ91

为了进一步提高镁合金表面磷化膜的耐腐蚀性能,采用锌系磷化液对AZ91镁合金进行磷化处理。采用扫描电镜及能谱仪分析磷化膜的形貌及成分;采用浸泡试验和极化曲线分析磷化膜的耐腐蚀性能。通过正交试验优选磷化液配方。结果表明:最优磷化工艺为2.0 g/L氧化锌,5 m L/L磷酸,0.2 g/L十二烷基磺酸钠,0.1 g/L酒石酸,0.2 g/L钼酸铵,0.3 g/L氟化钠,时间40 min,温度40℃,pH值2.5;优化工艺下所得磷化膜微观形貌均匀细致、厚度均匀、腐蚀失重小、腐蚀电流密度低,可有效地抑制镁合金的腐蚀。

Cailiao Baohu 2016,49(10),59-61(Ch).In order to improve the corrosion resistance,the phosphating process was conducted on AZ91 magnesium alloys,using zinc series phosphating solution.Surface morphology and components of phosphatizating film were observed and analyzed using scanning electron microscope(SEM) and energy depressive spectroscopy.The corrosion resistance was studied by the immersion test and polarization curves method.The basal phosphatizating formula and process were optimized by orthogonal experiment.Results showed that the optimized technique was as follows;2.0 g/L.ZnO,5mL/L H_3PO_4,0.2 g/L sodium dodecyl sulfate(SDS),0.1 g/L tartaric acid,0.2 g/L ammonium molybdate,0.3 g/L inhibitor,time 40 min,temperature 40 ℃ and pH value 2.5.Under the condition of optimization,the micromorphology of the phosphatizating films on magnesium alloy AZ91 surface was smooth and compact,and its thickness was uniform.Moreover,the films had small corrosion weight loss and low corrosion current density,which could inhibit the corrosion of magnesium alloys efficiently.