土壤腐蚀过程中高锡青铜的形貌变化和元素迁移

Morphology change and elements migration of bronze with high tin content after soil corrosion

采用在含模拟土壤介质(0.010 4 mol/L Na2SO4+0.028 2 mol/L NaCl+0.016 4 mol/L NaHCO3)的土壤中埋藏铸造青铜试样的方法研究高锡青铜的土壤腐蚀规律;采用金相显微镜观察腐蚀前后青铜的结构变化,扫描电镜(SEM)并结合能谱(EDS)对微区成分进行分析;用X射线荧光光谱(XRF)检测埋藏试样周围土壤中元素含量,同时用残留因子fCu/Sn和fCu/Pb定量分析腐蚀产物中Cu、Sn和Pb的残留情况。结果表明:在该环境下高锡青铜腐蚀首先从α相与δ相界面开始,且α相先于δ相发生腐蚀,留下未腐蚀的岛屿状δ相;高锡青铜腐蚀过程中Cu优先向周围土壤中迁移,最终形成的含O、C腐蚀产物中富含Sn和Pb。

The soil corrosion rule of the bronze with high tin content was researched by burying the metal samples in the soil containing the simulated the edaphic elecrdyte （0.010 4 mol/L Na2SO4＋0.028 2 mol/L NaC1＋0.016 4 mol/L NaHCO3） aimed at simulating the underground water. The morphology change before and after the corrosion was observed by metalloscopy, and SEM combined with EDS was used to analyze the micro-area composition of the corroded sample. Further research with X-ray fluorescence spectrometry （XRF） was carried out to measure the content of the elements in the soil around the bronze sample. Then, factorsfCo/Sn andfCu/Pb were used to make a quantitative analysis of the residual elements Cu, Sn and Pb in the corrosion products. The results show that the corrosion firstly occurs on the interface between the a phase and o phase, a phase is prior to be corroded, with the island-shaped o phase uncorroded and left. Cu is prior to diffuse into the surrounding soil, leaving the corrosion products containing O and C rich in Sn and Pb.