Hg和Ga元素对Mg阳极材料组织和电化学腐蚀性能的影响(英文)

采用动电位极化、恒电流和交流阻抗测试方法研究了Hg和Ga元素对Mg2%Hg,Mg2%Ga和Mg2%Hg2%Ga合金电化学腐蚀性能的影响,并用扫描电镜、X射线衍射和能谱分析了上述合金的显微组织和腐蚀表面形貌。结果表明:Mg2%Ga合金是固溶体,Mg-2%Hg和Mg-2%Hg2%Ga合金的晶界有白色第二相。Mg-2%Ga合金的平均电位为1.48V,腐蚀电流密度为0.15mA/cm2,电化学活性差,耐腐蚀性能好。Mg-2%Hg-2%Ga合金的平均电位1.848V,腐蚀电流密度为2.136mA/cm2,电化学活性好,耐腐蚀性能差。MgHgGa合金的活化机制是Hg和Ga原子的溶解沉积。     

合金元素Ga和In对Mg阳极组织和电化学性能的影响

采用动电位极化和恒电流曲线测试合金元素Ga和In对Mg阳极材料电化学性能的影响。采用扫描电镜法分析Mg?In?Ga合金的显微组织和腐蚀表面,并用X射线衍射法检测Mg?0.8%In合金和Mg?0.8%Ga?0.3%In 合金的腐蚀产物。结果表明：Mg?xIn (x=0?0.8%)合金中没有第二相出现,Mg?0.8%In?xGa (x=0?0.8%)合金中存在富含Ga和In元素的晶间化合物。合金元素In和0.05%?0.5%Ga的添加提高了镁阳极的耐腐蚀性能,Ga元素的添加更促进了Mg?In合金的电化学活性。Mg?0.8%In?0.8%Ga合金的平均电位最负,为?1.682 V,此电位比AZ91D合金的?1.406 V更负。Mg?In?Ga合金的腐蚀类型是全面腐蚀,其腐蚀产物是Mg(OH)2。     

Influence of Mg21Ga5Hg3 compound on electrochemical properties of Mg-5%Hg-5%Ga alloy

The Mg-Hg-Ga alloys are widely used in high power the seawater batteries. Mg-5%Hg-5%Ga alloy was melted and heat treatments at 573-773 K were performed for different times. The electrochemical and corrosion behaviors of the Mg-5%Hg-5%Ga alloy were studied by means of potentiodynamic, galvanostatic and electrochemical impedance spectroscopy(EIS). Scanning electron microscopy(SEM), energy dispersive spectrometry(EDS) and X-ray diffractometry(XRD) were employed to characterize the microstructures of the alloy. The results demonstrate that the best electrochemical activity occurs in the Mg-5%Hg-5%Ga alloy with homogeneously dispersed Mg21Ga5Hg3 compound in α-Mg matrix. The most negative mean potential at 100 mA/cm2 polarization current density can reach -1.928 V. The largest corrosion current density 19.37 mA/cm2 of the Mg-5%Hg-5%Ga alloy appears in the Mg-5%Hg-5%Ga alloy with intergranular eutectic α-Mg and Mg21Ga5Hg3.     

Mg和RE合金化对Al-Zn-Bi合金阳极组织和电化学性能的影响

针对Al-Zn-Bi合金,分别单独及复合添加Mg、RE元素进行微合金化,利用金相、扫描电镜及X射线能谱等分析了该合金添加不同元素前后的微观组织特征;采用恒电流法测定了该系列合金在人造海水中的开路电位、工作电位和电流效率,利用极化曲线和电化学阻抗谱,分析了微合金化对Al-Zn-Bi阳极材料电化学性能的影响。结果表明：单独添加Mg、RE可以细化晶粒、改善偏析相的组成和分布,将电流效率提高15.93%和4.12%;二者复合添加虽电流效率稍有降低,但可促使基体均匀溶解,减小腐蚀电流密度,从而有效提高其综合性能。     

Influence of Mg and Ti on the microstructure and electrochemical performance of aluminum alloy sacrificial anodes

The experiments focused on the influence of magnesium and titanium as additional alloying elements on the microstructure and electro-chemical behavior of Al-Zn-In sacrificial anodes. The electrochemical behavior of the aluminum sacrificial anode with 3 wt.% sodium chloride solution was studied by electrochemical impedance spectroscopy (EIS) tests. It was found that a microstructure with few precipitates and refined grains could be achieved by adding 1 wt.% Mg and 0.05 wt.% Ti to the Al-Zn-In alloy,resulting...     

Influence of aluminium and lead on activation of magnesium as anode

Mg-6%Al,Mg-5%Pb and Mg-6%Al-5%Pb (mass fraction)alloys were prepared by induction melting with the protection of argon atmosphere.Their electrochemical activations in different electrolyte solutions were investigated by galvanostatic test.The microstructures of these alloys and their corroded surfaces were studied by scanning electron microscopy,X-ray diffractometry and emission spectrum analysis.The results show that the activation of magnesium is not prominent when only aluminum or lead exists in the magnesium matrix,but the coexistence of the two elements can increase the activation.The activation mechanism of Mg-Al-Pb alloy is dissolving-reprecipitating and there is a synergistic effect between aluminium and lead:the precipitated lead oxides on the surface of the alloy can facilitate the precipitation of Al(OH)3,which can peel the Mg(OH)2 film in the form of 2Mg(OH)2·Al(OH)3 and activate the magnesium matrix.     

Effect of rolling processing on microstructure and electrochemical properties of high active aluminum alloy anode

The effect of rolling processing on the microstructure,electrochemical property and anti-corrosion property of Al-Mg-Sn-Bi-Ga-In alloy anode in alkaline solution(80℃,Na2SnO3+5 mol/L NaOH)was analyzed by the chronopotentiometry (E-T curves),hydrogen collection tests and modern microstructure analysis.The results show that when the rolling temperature is 370℃,the electrochemical activity of Al anode decreases gradually with the increase of pass deformation in rolling,while the anti-corrosion property is improved in the beginning and then declined rapidly.When the pass deformation of rolling is 40%,the Al anode has good electrochemical activity as good as the anti-corrosion property and with the increase of rolling temperature,both electrochemical activity and anti-corrosion property of Al anode increase first and then decrease.When the rolling temperature is 420 ℃,the aluminum alloy anode has the most negative electrode potential of about-1.521 V(vs Hg/HgO)and the lowest hydrogen evolution rate of 0.171 6 mL/(min·cm2).The optimum comprehensive performance of Al alloy anode is obtained.     

Mg对Al-Zn-Sn阳极合金组织与电化学性能的影响

为提高Al-7Zn-0.1Sn(质量分数,%)牺牲阳极的电化学性能,采用扫描电镜(SEM)、透射电镜(TEM)、动电位极化、电化学阻抗等方法,研究了不同含量的Mg对Al-7Zn-0.1Sn合金微观组织和电化学性能的影响。结果表明:Mg可使Al-7Zn-0.1Sn合金从粗大枝状晶向等轴晶转变;适量Mg可改善Al-7Zn-0.1Sn合金的电化学性能;随着Mg含量增加,合金电位负移、电流效率逐步提高;当Mg含量为2%时,合金具有最好的综合电化学性能。     

LC4铝合金剥蚀及其电化学阻抗行为

研究了LC4铝合金双级过时效处理板材在EXCO剥蚀溶液中的剥蚀行为及其相应的电化学阻抗谱。结果表明 ,腐蚀由晶界孔蚀发展为沿平行于表面的晶界腐蚀 ,并在晶界堆积大体积的楔形腐蚀产物 ,挤压表层晶粒而导致剥蚀。由于双级过时效处理使强化相 η均匀析出 ,降低了合金的晶间腐蚀程度 ,导致合金剥蚀程度很轻 ,主要表现为局部小面积的金属表层鼓泡剥蚀。剥蚀后 ,电化学阻抗谱由两个容抗弧组成 ,其中高频容抗弧源于合金原表面 ,而中低频容抗弧源于剥蚀后露出并与腐蚀介质接触的新界面。有可能根据这两个容抗成分的分析来定量判断合金的剥蚀程度。     

Effect of Ti and Zr elements with equal mass ratio on microstructure and corrosion resistance of Zn-11Al-3Mg alloy

In this study, the effect of Ti and Zr elements with equal mass ratio on microstructure and corrosion resistance of Zn-11Al-3Mg alloy was investigated. The microstructure was significantly refined and Al-rich phase transformed from dendrite to petal-like with the addition of Zr and Ti elements, due to the Al₃(Ti_xZr_{1 − x}) phase as the nucleation substrate. The corrosion resistance of Zn-11Al-3Mg-x(Ti,Zr) alloy was effectively improved. Moreover, the corrosion products of Zn-Al-Mg alloy were not changed by the addition of Ti and Zr, which are mainly composed of Zn₅(OH)₈Cl₂·H₂O and Zn₆Al₂(OH)₁₆CO₃·4H₂O.     

合金元素Ga对Al-Zn-Bi系阳极材料腐蚀机理的影响

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。     

镁含量对Al-Ga-Mn阳极合金组织和电化学性能的影响

制备了5种不同Mg含量的Al-Ga-Mn-Mg阳极合金,通过扫描电镜观察了合金的显微组织和腐蚀形貌,并测试了合金在40℃、4 mol·L-1Na OH溶液中的开路电位、交流阻抗谱、极化曲线及恒电流放电曲线,从而研究了Mg含量对Al-Ga-Mn合金组织和电化学性能的影响。结果表明:在Al-Ga-Mn合金中加入Mg元素之后,组织中析出相数量明显增多且均匀分布;另外,Mg元素显著改善了合金的电化学性能,降低其析氢速率。当Mg含量为1.5%时,合金表现出较优的综合性能,具有均匀的腐蚀形貌和较负开路电位、工作电位。     

热处理对Al-Zn-Sn-Ga-Mg合金组织和电化学性能的影响

通过比较铸态、退火和固溶态Al-Zn-Sn-Ga-Mg合金的组织和电化学性能,研究了热处理对该阳极微观组织和电化学性能的影响。结果显示：均匀化处理能减少阳极晶界偏析,抑制析氢腐蚀和提高阳极电流效率,且固溶处理的效果明显优于退火处理。经固溶处理后阳极的电流效率达93.4%,工作电位负而稳定,且腐蚀形貌均匀,表明该合金具有较好的综合电化学性能。     

轧制及热处理对Mg-Hg-Ga合金组织和电化学性能的影响

采用SEM、XRD和电化学方法研究Mg-Hg-Ga合金在铸态、均匀化处理态、轧制态等不同状态下的显微组织和电化学性能;对轧制后的Mg-Hg-Ga合金板材在150～300℃下退火,研究退火温度对其显微组织和电化学性能的影响。结果表明:400℃保温24 h可以消除合金非平衡凝固时的合金元素在晶界处的偏聚,并改善了合金的电化学性能。经多道次热轧后的Mg-Hg-Ga合金板材在不同温度退火后,材料的电化学活性随退火温度的升高先提高后有所降低,在250℃退火4 h达到最高,稳定电位为-1.849 V;耐腐蚀性能随退火温度的升高不断降低,退火温度从150℃升高到300℃时,材料的腐蚀电流密度从3.525×10-4 A/cm2增大到2.438×10-3 A/cm2。这与合金中弥散分布的球状析出相的数量和尺寸有关。     

Microstructural evolution and corrosion behavior of friction stir processed fine-grained AZ80 Mg alloy

Friction stir processing (FSP) and subsequent aging heat treatment were used to modify the microstructure of AZ80 magnesium alloy. The influence of FSP and aging heat treatment on the corrosion behavior was systematically studied by using potentiodynamic polarization, immersion, and slow strain rate tensile tests. The results revealed that FSP led to grain refinement, rapid dissolution of β-phase, and the deflection of c-axis from transverse direction (TD) and processing direction (PD) by approximately 55° and 25°, respectively, improving the static corrosion and stress corrosion cracking (SCC) resistance. The aging heat treatment rendered a little influence on the grain size and slightly affected the grain orientation. The content of β-phase in FSP-5 and FSP-24 samples was 8.1 and 21.8 wt.%, respectively. Static corrosion and SCC resistance of FSP-5 and FSP-24 samples were lower than those of the FSP samples. Compared with FSP-5 sample, the amount of β-phase and the proportion of Al₂O₃ increased in FSP-24 sample, leading to enhanced static corrosion and SCC resistance. SCC behavior was controlled by anodic dissolution, whereas the presence of hydrogen accelerated the SCC.     

Al-Zn-Sn-Ga阳极腐蚀过程的电化学阻抗谱

通过测定Al-Zn-Sn-Ga阳极在3.5%NaCl(质量分数)溶液中浸泡不同时间的电化学阻抗谱(EIS),研究该阳极的腐蚀发展过程和腐蚀特征。结果显示:当合金刚被浸入3.5%NaCl溶液时,EIS谱为反应电阻很大的容抗弧,表明此时合金处于钝化态;随着浸泡时间的延长,EIS谱中高频段的容抗弧明显减小且低频段出现感抗弧,合金进入点蚀期;继续延长浸泡时间,EIS谱中除高频段的容抗弧和中、低频段感抗弧外,在低频段出现另一容抗弧,合金处于点蚀扩展期;随着浸泡时间的继续增加,低频段感抗弧消失,EIS谱由两个容抗弧组成,合金达到均匀腐蚀期。因此,合金的腐蚀由钝化态开始,经点蚀期和点蚀扩展期,达到均匀腐蚀期。     

A dense and compact laser cladding layer with solid metallurgical bonding significantly improved corrosion resistance of Mg alloy for engineering applications

Although Mg alloy attracts great attention for engineering applications because of high specific strength and low density, low corrosion resistance limits its extensive use. In this study, Mg–Al–Zn–Mn alloy was treated via a laser cladding process to generate a dense and compact laser cladding layer with solid metallurgical bonding on the substrate for improving corrosion resistance, effectively hindering the corrosion pervasion into Mg alloy. The corrosion current density declined from 103 μA/cm² for Mg alloy to 13 μA/cm² for the laser cladding layer in NaCl aqueous solution. Moreover, the laser cladding layer was slightly corroded in comparison with Mg alloy in NaCl aqueous solution. Besides, the microhardness of the cladding layer reached a mean value of 170.5 HV, 3.1 times of Mg alloy (56.8 HV) due to the in situ formation of hardening intermetallic phases. Wear resistance of laser cladding layer was also obviously improved. These results demonstrated that the laser cladding layer obviously enhanced anticorrosion property of Mg alloy for engineering applications.     

Stress corrosion behavior of 6082 aluminum alloy

Stress corrosion tests of 6082 aluminum alloy were carried out by using a three-point bending fixture while holding at 50% of yield strength state through different immersion times in 1.5% NaCl electrolyte solution. The electrochemical impedance spectra and dynamic electric potential polarization curves were measured to indicate the stress corrosion behavior of the alloy. Optical microscopy, scanning electron microscopy, and X-ray energy spectrum analysis were applied for microstructural investigations. The results show that all of the Nyquist electrochemical impedance spectra consisted of high- and low-frequency double capacitive arcs. However, an increase in immersion time while holding at 50% of yield stress resulted in a corresponding increase in the corrosion current density, leading to gradual corrosion depth growth, and a decrease in the corrosion resistance of the alloy. 6082 Aluminum alloy included AlMnFeSi, Mg₂Si, and Si secondary phases. The different secondary phases presented different stress corrosion behaviors. Stress corrosion cracks were generated at the boundaries of AlMnFeSi and matrix or within the AlMnFeSi phase. Crack direction is always perpendicular to the tensile stress applied. Mg₂Si secondary phase was self-corroded as its corrosion potential is lower than that of the matrix. As the electric potential of Si is higher than that of the matrix, corrosion occurred at the matrix side of the boundary between Si and matrix.