(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 采用熔煉鑄造法制備Mg合金陽極材料，采用恒電流法和動電位極化掃描法研究合金成分和熱處理對其電化學(xué)行為的影響，采用光學(xué)顯微鏡、掃描電鏡和X射線衍射儀對不同熱處理狀態(tài)下顯微組織和腐蝕產(chǎn)物進(jìn)行觀察和檢測。結(jié)果表明：隨著Hg含量的增加，固溶態(tài)試樣在100 mA/cm2放電電流密度下的穩(wěn)定電位由−1.547 V降至−1.772 V，Hg對Mg陽極材料具有較強(qiáng)的活化作用。熱處理使Mg陽極第二相Mg5Ga2沿晶界和晶內(nèi)彌散析出。Mg合金陽極材料的電化學(xué)活性由大至小的順序?yàn)殍T態(tài)、96 h時效態(tài)、2 h時效態(tài)、固溶態(tài)，而腐蝕抗力卻按此順序依次增大，Mg合金陽極材料的腐蝕類型為全面腐蝕與點(diǎn)蝕共存。
關(guān)鍵字: Mg陽極；時效處理；電化學(xué)性能；腐蝕抗力；合金化
electrochemical behavior of Mg anode
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Mg anode materials were prepared by melting and casting. The effects of chemical composition and heat treatment on the electrochemical corrosion behavior of Mg anode materials were investigated by potentiodynamic polarization and galvanostatic tests. The scanning electron micrographs of the secondary phase after aging treatment and the corroded surface of specimens after galvanostatic test were observed by OM, SEM and XRD. The results show that the stable potential of Mg anode materials decreases from −1.547 V to −1.772 V with the increase of Hg contents, Hg is an activator element of Mg anode materials. The Mg5Ga2 phase precipitates homogeneously along the grain boundary and within the grain when the Mg-Hg-Ga alloys were aged at 200 ℃ for 96 h. The order from big to small of the electrochemical activity of the alloys is the as-cast specimens, the specimens aged at 200 ℃ for 96 h, the specimens aged at 200 ℃ for 2 h and super-saturated solid solution, and the corrosion resistance of the alloys follows the opposite order. The corrosion of the aged Mg-Hg-Ga alloy is mainly generous attack and pitting attack.
Key words: Mg anode; aging treatment; electrochemical property; corrosion resistance; alloying
