摘要
采用腐蚀失重法研究了Ag-Cu-Al-Y合金在Na2S溶液中的腐蚀动力学行为,利用金相(OM)、扫描电子显微镜(SEM)和能谱(EDS)等手段分析了合金腐蚀前后显微组织,探讨了Ag-Cu-Al-Y合金在Na2S溶液中的腐蚀机理。结果表明,添加稀土Y能明显改善Ag-Cu-Al的抗硫化腐蚀性能,其中添加0.03at%Y的银合金具有最小的硫化腐蚀速率。在Ag-Cu-Al-Y合金的硫化腐蚀过程中,腐蚀优先发生在晶界处,腐蚀过程首先形成保护性的致密氧化物层(Y2O3和Al2O3),阻碍氧、硫离子进一步扩散;随着氧化层的逐步剥落,氧、硫离子迅速扩散进入合金内部,并优先与Cu反应形成Cu2S。腐蚀产物内层组织主要为致密氧化物层,外层疏松组织为氧化物和硫化物共存组织。
The corrosion behaviors of Ag-Cu-Al-Y alloys in Na2S solution were investigated based on the kinetics of corrosion weight loss analysis, the microstructure characterization was analyzed by optical microscope（OM）, scanning electron microscope（SEM） and energy diffraction spectrum（EDS）. The results indicated that the corrosion resistance of Ag-Cu-Al alloys was improved by the addition of Y, and the best performance was exhibited in the alloy with 0.03at% Y. The sulfuration corrosion of Ag-Cu-Al-Y alloys occurred preferentially at the grain boundaries. A dense protective oxide layer composed of Y2O3 and Al2O3 was formed firstly, which prevents further diffusion of oxygen and sulfur ions. With the external oxide layer peeling off, oxygen and sulfur ions diffused rapidly into the internal alloy and preferentially reacted with Cu to form Cu2S. The corrosion layer was constructed by two layers, an inner layer of dense oxide and a loose outer layer of oxides and sulfides mixture.
出处
《贵金属》
CAS
CSCD
北大核心
2014年第1期36-42,共7页
Precious Metals
基金
国家科技支撑计划(2011BAE09B03)
