(1. 沈陽建筑大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110168；
2. 沈陽建筑大學(xué) 交通與機械學(xué)院，沈陽 110168；
3. 中國科學(xué)院 金屬研究所 金屬腐蝕與防護國家重點實驗室，沈陽 110016)
摘 要: 通過設(shè)計三電極電化學(xué)系統(tǒng)，采用循環(huán)伏安、動電位陽極極化以及恒電位陽極極化方法研究了銀在不同氫氧化鈉溶液的電化學(xué)行為。結(jié)果表明：銀在NaOH溶液中，循環(huán)伏安和動電位陽極極化正向掃描中出現(xiàn)Ag2O和AgO的氧化峰。隨著NaOH濃度的增加，在相同電極電位條件下，陽極電流密度逐漸增加，極化后銀的腐蝕增質(zhì)也隨之增加；極化后樣品表面的腐蝕產(chǎn)物聚集更為嚴重，出現(xiàn)較多的孔洞和微裂紋，從而為電解質(zhì)溶液和基體之間的物質(zhì)傳輸提供了更多通道，加速了銀的電化學(xué)腐蝕進程。
關(guān)鍵字: 銀；氫氧化鈉溶液；循環(huán)伏安；動電位陽極極化；恒電位陽極極化
（1. School of Materials Science and Engineering, Shenyang Jianzhu University, Shenyang 110168, China;
2. School of Traffic and Mechanical Engineering, Shenyang Jianzhu University, Shenyang 110168, China;
3. State Key Laboratory for Corrosion and Protection, Institute of Metal Research,
The Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The electrochemical behaviors of silver in NaOH solution were investigated via cyclic voltammetry, anodic polarization, mass gain and scanning electron microscope. The results reveal that the current density peak of Ag2O forms and follows with the formation of AgO during the anodic polarization. Anodic current density of silver decreases sharply to a stable value, and silver oxide with the same size are formed on silver’s surface under potentiostatic polarization in the three NaOH solutions. The higher the NaOH concentration is, the denser the silver oxides distribute on the surface of silver. At the same potential for the potentiodynamic polarization curves of silver, the anodic current density of silver increases with NaOH concentration increasing. Mass gain of the potentiodynamic anodic polarized silver increases with NaOH concentration as well. The morphologies of the potentiodynamic anodic polarized silver shows that the corrosion products accumulate more severe and there are more micro-cracks on the surface of silver polarized with higher NaOH concentration than with lower NaOH concentration. The micro-cracks provide channels for ion transport, which is essential for further corrosion of silver in NaOH solution, through the corrosion products.
Key words: silver; NaOH solution; cyclic voltammetry; potentiodynamic polarization; potentiostatic polarization
