(1. 白云鄂博稀土資源研究與綜合利用國家重點(diǎn)實(shí)驗(yàn)室，包頭 014030；
2. 上海大學(xué) 材料科學(xué)與工程學(xué)院，上海 200444;
3. 上海大學(xué) 省部共建高品質(zhì)特殊鋼冶金與制備國家重點(diǎn)實(shí)驗(yàn)室，上海 200444;
4. 上海大學(xué) 材料基因組工程研究院，上海 200444)
摘 要: 采用熱浸鍍法在低碳鋼表面制備含Ce元素的鍍鋅層，利用光學(xué)顯微鏡(OM)、掃描電鏡(SEM)、X射線衍射儀(XRD)、中性鹽霧試驗(yàn)(NSS)以及電化學(xué)測試方法，揭示不同Ce元素添加量對鍍層微觀組織結(jié)構(gòu)及耐蝕性能的影響規(guī)律。結(jié)果表明：在鍍液中添加適量的Ce元素可在細(xì)化鍍鋅層晶粒和減薄鍍鋅層厚度的同時(shí)有效地提高鍍鋅層的耐蝕性。與純鋅鍍層相比，鍍液中添加0.012%和0.2%Ce(質(zhì)量分?jǐn)?shù))后鍍層的腐蝕速率分別降低24%和27%。Ce元素提高鍍鋅層耐蝕性的機(jī)理為：一方面，Ce的添加提高了腐蝕產(chǎn)物中Zn5(OH)8Cl2？H2O占比，從而提高了腐蝕產(chǎn)物的致密性與粘附性；另一方面，腐蝕過程所形成的Ce(OH)3沉淀吸附在陰極相，阻礙氧的擴(kuò)散，抑制了陰極吸氧反應(yīng)。當(dāng)鍍液中添加超過0.012%Ce后(過飽和)，陰極反應(yīng)已被充分抑制，因而繼續(xù)提高Ce添加量對鍍鋅層耐蝕性的提高有限。
關(guān)鍵字: 熱浸鍍；稀土元素；鍍鋅層；耐蝕性；電化學(xué)行為
（1. State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization, Baotou 014030, China;
2. School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China;
3. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200444, China;
4. Materials Genome Institute, Shanghai University, Shanghai 200444, China）
Abstract:Zinc coatings containing rare earth element Ce were prepared on a mild steel surface by hot dipping, the effects of Ce on the microstructure and corrosion resistance of galvanized coating were studied by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffractometry (XRD), neutral salt spray (NSS) test and electrochemical methods. The results show that the addition of Ce in the hot dipping liquid increases the corrosion resistance of the coating considerably while refining the grain size and reducing the thickness. Compared with the pure zinc coating, the coatings prepared with hot dipping liquids with 0.012% and 0.2% (mass fraction) Ce added are reduced by 27% and 23% in thickness and 24% and 27% in corrosion rate, respectively. The enhancement of corrosion resistance by Ce addition comes from two ways, one is that the addition of Ce increases the proportion of Zn5(OH)8Cl2？H2O, which can improve the compactness and adhesiveness of the corrosion product. The other is that the formed Ce(OH)3 deposited on the cathodic phase impedes the diffusion of oxygen, thereby inhibiting the cathodic reaction. The enhancement reaches the limit since the cathodic reaction has been fully inhibited when the Ce content in hot dipping liquid exceeds 0.012% (supersaturation).
Key words: hot dipping; rare earth element; hot-dip coating; corrosion resistance; electrochemical behavior
