(中國科學院 金屬研究所 沈陽材料科學國家(聯合)實驗室，沈陽 110016)
摘 要: 通過沈陽大氣環(huán)境下的自然暴露實驗研究工業(yè)純Sn和Sn-3Ag-0.5Cu合金的早期大氣腐蝕行為。采用掃描電子顯微鏡(SEM)和X射線光電子能譜儀(XPS)分析了表面腐蝕產物的形貌與成分。結果表明：工業(yè)純Sn與Sn-3Ag-0.5Cu合金在沈陽工業(yè)大氣環(huán)境下自然暴露后都很快發(fā)生了表面腐蝕并失澤，早期腐蝕產物疏松、龜裂并易于剝落。XPS深度分析表明：自然條件下暴露18 d后，表面腐蝕產物層厚度約為400 nm。工業(yè)大氣中的懸浮物顆粒對腐蝕的形核和擴展起重要作用，Sn-3Ag-0.5Cu合金中的第二相Ag3Sn和Cu6Sn5作為陰極存在，但對大氣腐蝕的加速影響不大。
關鍵字: Sn；Sn-3Ag-0.5Cu合金；無鉛焊料；大氣腐蝕
（Shenyang National Laboratory for Materials Science, Institute of Metal Research,
Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The atmospheric corrosion behavior of industrial pure Sn and Sn-3Ag-0.5Cu alloy was investigated through natural exposure test in atmospheric environment of Shenyang. The morphologies and compositions of surface corrosion products were analyzed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that, after a short exposure in atmospheric environment of Shenyang, both the industrial pure Sn and Sn-3Ag-0.5Cu alloy tarnish and form a layer of corrosion products quickly. The initial corrosion products are loose, with many cracks and easily falling off. The thickness of corrosion products layer is about 400 nm measured by XPS depth analysis. The dust (suspended particulates) in the industrial atmosphere plays an important role in the nucleation and development in corrosion process. The second phase particles Ag3Sn and Cu6Sn5 in Sn-3Ag-0.5Cu alloy act as cathode in the atmospheric corrosion, but they have little influence on the acceleration of the corrosion process.
Key words: Sn; Sn-3Ag-0.5Cu alloy; lead free solder; atmospheric corrosion
