不同B含量的Pb-Mg-Al-B合金在Cl^-中的腐蚀行为

Chloride Ions on Corrosion Behavior of Pb-Mg-Al-B Alloys with Different B Content

采用模拟海水浸泡实验、析氢腐蚀、中性盐雾腐蚀试验、电化学法测试,并采用静态腐蚀失重法测定计算合金腐蚀速率,研究了具有核屏蔽性能的Pb-Mg-Al-B合金在3.5wt.%NaCl溶液中的腐蚀行为,并利用SEM、XRD以及XPS对腐蚀前后合金的表面形貌和腐蚀产物进行分析。结果表明:B含量为1.5%时合金的耐腐蚀性能最好;第二相Mg17Al12以网状形态分布于晶界时对合金腐蚀有明显的阻碍作用;XRD表明腐蚀产物主要为Mg2Pb、PbO、Pb、以及Al2O3、Mg17Al12和含B相AlB2,几乎没有Mg的衍射峰;造成耐蚀性差异的主要原因在于不同元素金属含量对合金微观组织结构的影响。

Corrosion behavior of Pb-Mg-Al-B investigated by immersion tests, neutral salt spray, shielding functional material in 3.5wt. %NaCl solution was electrochemical measurements and static weight loss test. The surface morphology and corrosion products of alloys were observed by using scanning electron microscopy （SEM）, X-Ray Diffraction （XRD）, Energy Dispersive Spectrometer （EDS） and X-ray Photoelectron Spectroscopy （XPS）. It is found that the Pb-Mg-A1-B alloy with 1.5% B has the highest corrosion resistance, and the reticular Mg17 Al1~ phase distributed in the grain boundary play a visible role of hindrance to corrosion. The major corrosion products are Mg2Pb, PbO, Pb, Al2O3, Mg17Al12 and AlB2. The main reason of different corrosion resistances of Pb-Mg-Al-B alloys is due to the effect of different element contents on microstructures of alloys.