(中國(guó)鋼研科技集團(tuán)有限公司 先進(jìn)金屬材料涂鍍國(guó)家工程實(shí)驗(yàn)室，北京 100081)
摘 要: 應(yīng)用電化學(xué)阻抗譜(EIS)連續(xù)測(cè)試B95鋁合金表面稀土轉(zhuǎn)化膜在3.5%NaCl溶液中鈰鹽轉(zhuǎn)化膜的破壞過程，通過阻抗值的變化研究B95鋁合金表面稀土轉(zhuǎn)化膜在3.5%NaCl溶液中的腐蝕行為，采用等效電路的方式對(duì)測(cè)試的EIS進(jìn)行解析。通過轉(zhuǎn)化膜腐蝕過程阻抗譜特征研究，建立了B95鋁合金表面Ce(Ⅲ)轉(zhuǎn)化膜腐蝕破環(huán)的3個(gè)階段模型：浸泡早期、浸泡中期和浸泡后期。浸泡早期，鋁合金表面稀土轉(zhuǎn)化膜被電解質(zhì)溶液濕潤(rùn)，水開始滲透進(jìn)轉(zhuǎn)化膜；浸泡中期，電解質(zhì)溶液滲透轉(zhuǎn)化膜被破壞，同時(shí)與轉(zhuǎn)化膜自修復(fù)相互競(jìng)爭(zhēng)，轉(zhuǎn)化膜破壞/再鈍化；浸泡后期，轉(zhuǎn)化膜破壞超過轉(zhuǎn)化膜自修復(fù)，鋁合金基體開始逐漸腐蝕溶解。同時(shí)，該模型可以定量預(yù)測(cè)轉(zhuǎn)化膜表面腐蝕發(fā)展的程度。
關(guān)鍵字: 鋁合金；電化學(xué)阻抗；Ce轉(zhuǎn)化膜；腐蝕行為；NaCl溶液
（National Engineering Laboratory for Advanced Coatings Technology of Metal Materials,
China Iron and Steel Research Institute Group, Beijing 100081, China）
Abstract:The corrosion behavior of cerium(Ⅲ) conversion coating on B95 aluminum alloy in 3.5%NaCl solution was investigated by electrochemical impedance spectroscope (EIS). The process of corrosion and mechanism of cerium(Ⅲ) conversion coating on B95 aluminum alloy were investigated through the changes of EIS in the process. The tested EIS based on equivalent circuit was analyzed. The results show that the variation of EIS can clearly display the corrosion behavior change of cerium(Ⅲ) conversion coating on B95 aluminum alloy in 3.5%NaCl solution. Through investigating the EIS features, the respective model of each stage and its corresponding equivalent circuit were built to show the corrosion and destruction of the Ce(Ⅲ) conversion coating on B95 aluminum alloy. They are, respectively, the early stage, the middle stage and the terminal stage of immersion. The early stage refers to the time when the conversion coating on aluminum alloy is moisturized by electrolyte solution and water begins to permeate into the coating. The middle stage refers to the time when this permeation into the conversion coating is destructed while the conversion coating undergoes self-rehabilitation, thus giving rise to the competition between the destruction and self-rehabilitation of the conversion coating. The terminal stage refers to the time when the destruction of conversion coating outweighs its self-rehabilitation, the alloy begins to get corroded and resolved. This model can predict the corrosion degree of the conversion coating surface.
Key words: aluminium alloys; electrochemical impedance spectroscope (EIS); cerium conversion coating; corrosion behavior; NaCl solution
