摘要
采用恒电流法测定了添加Ga元素前后的Al-Zn-Bi系合金在人造海水中的开路电位、工作电位和电流效率,观察了该试验过程后合金的表面腐蚀形貌;利用极化曲线和电化学阻抗谱研究了该阳极合金在3.5%NaCl溶液中腐蚀过程的演变规律。结果表明:Ga能使Al-Zn-Bi系合金开路电位负移,工作电位稳定,电流效率升高,腐蚀形貌更加均匀;Ga可均匀固溶于铝合金中,并与回沉积的阳离子形成Ga基汞齐,使得阳极合金的活化控制步骤由第二相粒子优先溶解-脱落机理转变为金属阳离子的溶解-再沉积机理,促进阳极合金的均匀溶解,从而提高其综合电化学性能;等效电路RL(Cs(CpRp)(Q1Rd1)(LRa))和RL(Cs(CpRp)(Q1Rd1)(LRa)(Q2Rd2))能较好地表征两种合金的腐蚀行为和活化机理。
The open circuit potential,working potential,current efficiency and surface corrosion morphology of Al-Zn-Bi alloy before and after adding Ga element in artificial seawater were tested and observed by constant current method.The corrosion characteristics of the anode alloys in 3.5% NaCl solution were investigated by polarization curves and electrochemical impedance spectra.The results show that the open circuit potential shifts towards negative,working potential becomes stable,the current efficiency improves and corrosion morphology becomes uniform through the addition of gallium in the alloy.Gallium can be uniformly dissolved into aluminum alloy and the cations can deposit back to the anode surface forming into the Ga-Al amalgam.The activation control step of anode alloy transforms from the preferential dissolution-shed mechanism of second phase particles to the dissolution-redeposition mechanism of metal cations,which promotes its homogeneous dissolution and improve comprehensive electrochemical performance.Through analysis,the different activation mechanism can be characterized by the equivalent circuits of RL（Cs（CpRp）（Q1Rd1）（LRa）） and RL（Cs（CpRp）（Q1Rd1）（LRa）（Q2Rd2）） fitted the EIS in 3.5% NaCl solution of those two alloys.
出处
《金属热处理》
CAS
CSCD
北大核心
2011年第8期25-29,共5页
Heat Treatment of Metals
基金
河南省科技创新杰出人才计划(094200510019)
河南省自然科学基金项目(092300410132)
河南科技大学青年科学基金项目(2010QN0022)
关键词
Al-Zn-Bi系合金
GA
电化学性能
电化学阻抗谱
腐蚀机理
Al-Zn-Bi series alloy
Ga
electrochemical properties
electrochemical impedance spectroscopy
corrosion mechanism
