LZ91镁锂合金植酸处理工艺及耐腐蚀性能研究

Phytic acid treatment process and corrosion resistance of LZ9191 magnesium lithium alloymagnesium lithium alloy

为了改善LZ91镁锂合金的耐腐蚀性能,采用正交试验法对厚度为3 mm的商用轧制态双相LZ91镁锂合金板材表面进行植酸化学转化处理,借助扫描电子显微镜、电化学工作站等设备对不同植酸转化处理的自腐蚀电流密度进行研究,并探讨植酸化学转化液浓度、转化时间、pH值和转化温度对LZ91镁锂合金耐腐蚀性能的影响,得出最佳耐腐蚀性能的植酸化学转化工艺参数。结果表明:对LZ91镁锂合金植酸化学转化处理影响最显著的是溶液pH值、其次为转化时间、再次为转化液浓度、最后则为转化温度;当植酸浓度为2 mL/L,转化时间为5 min,pH值为6和转化温度为35℃时,LZ91镁锂合金植酸化学转化处理后的耐腐蚀性能最佳,此时自腐蚀电流密度达到最小值2.254×10^(-5)A/cm^(2);与未植酸处理相比,自腐蚀电流密度下降了2个数量级,耐腐蚀性能得到很大提升。因此,植酸化学转化处理提升LZ91镁锂合金的耐腐蚀性能有一定的应用价值。

In order to improve the corrosion resistance of LZ91 magnesium lithium alloy,the phytic acid chemical conversion treatment was carried out on the surface of the commercial rolled dual-phase LZ91 magnesium lithium alloy plate with a thickness of 3 mm by using the orthogonal test method.With the help of scanning electron microscope,electrochemical workstation and other equipment,the self corrosion current density under the conditions of different phytic acid conversion treatment process parameters was studied,and the concentration of phytic acid chemical conversion solution,conversion time,pH value and conversion temperature on the corrosion resistance of LZ91 magnesium lithium alloy during phytic acid chemical conversion treatment,and the optimal process parameters for phytic acid chemical conversion treatment were obtained through data analysis.The results show that the degree of influence of process parameters on the chemical conversion treatment of LZ91 magnesium lithium alloy with phytic acid is as follows:pH value>conversion time>conversion solution concentration>conversion temperature.When the concentration of phytic acid is 2 mL/L,the conversion time is 5 min,the pH value is 6,and the conversion temperature is 35℃,the corrosion resistance of LZ91 magnesium lithium alloy after phytic acid chemical conversion treatment is the best.At this time,the self corrosion current density reaches the minimum value of 2.254×10^(-5)A/cm^(2).Compared with untreated with phytic acid,the self corrosion current density has decreased by two orders of magnitude,and the corrosion resistance has been greatly improved.Therefore,the chemical conversion treatment with phytic acid can improve the corrosion resistance of LZ91 magnesium lithium alloy,and has certain application value in alloy surface corrosion protection.