腐蝕電化學行為
(1. 上海交通大學 材料科學與工程學院 輕合金精密成型國家工程研究中心，上海 200240；
2. 上海交通大學 材料科學與工程學院 金屬基復合材料國家重點實驗室，上海 200240；
3. 上海交通大學 環(huán)境科學與工程學院，上海 200240；
4. 上海交通大學 機械與動力工程學院，上海 200240)
摘 要: 采用鹽水浸泡法和電化學方法研究AZ91D鎂合金和稀土鎂合金Mg-3.0Nd-0.2Zn-0.4Zr(NZK)在5%(質(zhì)量分數(shù))NaCl溶液中的腐蝕行為。結果表明：NZK的腐蝕速率僅為AZ91D鎂合金的1/2，這主要是由于NZK中陰陽極之間的電位差和陰陽極面積比小于AZ91D的所致；AZ91D的腐蝕主要集中在局部區(qū)域，形成較深的腐蝕坑，而NZK的腐蝕沿合金表面進行，形成比較均勻的淺腐蝕區(qū)域；NZK的腐蝕電位低于AZ91D的腐蝕電位； NZK稀土鎂合金的耐點蝕能力高于AZ91D的。
關鍵字: AZ91D鎂合金；Mg-RE合金；腐蝕行為；循環(huán)極化
（1. National Engineering Research Center of Light Alloys Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Science and State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering,
Shanghai Jiao Tong University, Shanghai 200240, China;
3. School of Environmental Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
4. School of Mechanical and Power Engineering, Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:The corrosion behaviour of AZ91D and Mg-3.0Nd-0.2Zn-0.4Zr (mass fraction, %) alloy was investigated in 5% (mass fraction) NaCl solution by immersion test and electrochemical measurements. The immersion test shows that the corrosion rate of NZK is only half of that of AZ91D, which is attributed to the higher potential difference of the cathode-to-anode phase and the anode matrix and higher cathode-to-anode area ratio of AZ91D than those of NZK. The corrosion of AZ91D concentrates on the certain areas and results in much deeper corrosion pits, while that of NZK spreads across the surface and leads to more uniform and shallow corroded areas. The corrosion potential of NZK is much lower than that of AZ91D indicated by the open circuit potential measurement. The cyclic polarization curves show that NZK alloy has higher pitting corrosion resistance than AZ91D.
Key words: AZ91D Mg alloy; Mg-RE alloy; corrosion behavior; cyclic polarization
