Ga含量对Al-Ga牺牲阳极电化学性能的影响

    设计并熔炼了不同Ga含量的Al-Ga二元合金牺牲阳极材料,采用恒电流方法研究了Al-Ga牺牲阳极在海水中的电化学性能及Ga含量对Al-Ga牺牲阳极电化学性能的影响,并利用XRD分析了腐蚀产物以及Al-Ga牺牲阳极材料的晶格参数.结果表明,随Ga含量的增加,阳极开路电位和工作电位均负移,电流效率降低;Ga以固溶形式存在于铝基体中.     

Al-Ga-Mg合金组织与阳极性能研究

在25℃、4 mol/LKOH溶液中,测定了固溶及未固溶的Al-0.05Ga-1Mg和Al-0.1Ga-1Mg合金的开路电位、工作电位、自腐蚀速率及阳极效率,电子探针（EPMA）分析了铝阳极的基体及偏析相.结果表明,随着Ga含量的增加,开路电位变负;铝合金的偏析相中主要含Fe、Si两种元素;Mg元素能较显著降低Al-Ga合金的自腐蚀;固溶处理增多了铝合金阳极的阴极相,阴极相的增加及脱落,增大了自腐蚀,使阳极效率降低.     

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。     

合金元素Ga在铝合金牺牲阳极中的应用

介绍了微量合金元素Ga在铝合金牺牲阳极中的应用和研究情况,综述了Ga对铝合金牺牲阳极电化学性能的影响及Ga对铝的活化作用机理,概述了本课题组对Al-Ga合金阳极的研究结果,展望了Al-Ga合金牺牲阳极的发展方向。     

η相在Al-Zn-In-Mg-Ti牺牲阳极合金中的活化作用

采用扫描电镜、透射电镜、X射线衍射、电化学性能测试等方法,研究了Al-5Zn-0.02In-1Mg-0.05Ti牺牲阳极合金中析出相的腐蚀行为。结果表明,该合金主要含η-MgZn2析出相。η析出相相对α-Al基体呈阳极相,在3.5%的NaCl溶液中与α-Al基体组成微腐蚀电池,引起析出相自身溶解。溶解的Zn2+沉积在蚀坑周围,增加这些位置氧化膜的缺陷,促使氧化膜脱落。该牺牲阳极合金的溶解是以η析出相为活化中心,由此向外扩展,引发合金全面溶解。     

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。     

In对Al-Mg-Ga-Sn-(In)铝合金阳极组织及电化学性能的影响

在Al基体中添加Mg、Ga、Sn、In合金元素,通过正交试验设计了9组铝-空气电池阳极材料。采用动电位极化试验、析氢试验和恒电流放电试验对铝合金阳极的电化学性能进行优化,通过扫描电镜和能谱测试仪观察了合金的显微组织及成分。结果表明,没有添加In元素的1号合金(Al-0.5Mg-0.05Sn-0.05Ga)、5号合金(Al-Mg-0.1Sn-0.2Ga)和9号合金(Al-2Mg-0.2Sn-0.1Ga)铝阳极具有较差的放电性能和较高的自腐蚀速率,而添加0.05wt% In元素的7号铝阳极(Al-2Mg-0.05Sn-0.2Ga-0.05In)具有最好的放电电压(平均电位-1.968 V)和抗腐蚀性能 (自腐蚀速率0.193 mL·cm^-2·min^-1)。对比去腐蚀产物后的合金表面形貌,发现5号合金的腐蚀表面布满较深的腐蚀坑,这增加了铝合金的自腐蚀,而7号合金的表面具有较浅的腐蚀坑,这减缓了电解液中离子传递和自腐蚀速率。 因此,7号铝合金适合用作铝-空气电池阳极材料。     

Al-Zn-Ga低驱动电位牺牲阳极的设计及其电化学性能

根据正交试验表设计了16种Al-Zn-Ga低驱动电位牺牲阳极的合金配方,采用恒电流法评价了这些阳极的电化学性能,并观察其腐蚀形貌。结果表明：随着阳极中Zn和Ga含量的升高,阳极工作电位负移;其中,最佳Al-Zn-Ga阳极的合金配方为Al-0.25Zn-0.05Ga,该配方牺牲阳极的工作电位为-800～-750 mV,电容量最高,达到2 426 A·h/kg。     

合金元素对铝基牺牲阳极性能的影响

通过合金化方法,在Al-Zn-In三元牺牲阳极中依次添加Mg、Ti、Ga、Mn、Sn等元素,炼制不同成分的铝合金牺牲阳极。采用电化学性能测试、极化曲线测量及扫描电子显微镜分析等手段分析了合金元素对铝合金牺牲阳极性能的影响。结果表明,随着添加元素种类的增加,牺牲阳极电化学性能提高。在Al-Zn-In三元阳极中加入Mg和Ti,阳极溶解形貌更加均匀;加入Ga与Sn后,阳极的开路电位与工作电位负移;加入Mn后阳极的电流效率提高。     

Influence of Ga and Hg on microstructure and electrochemical corrosion behavior of Mg alloy anode materials

The effects of Hg and Ga on the electrochemical corrosion behavior of Mg-5%Hg （molar fraction） alloys were investigated by the measurement of polarization curves and galvanostatic test. The microstructure of the alloys and the corroded surface of the specimens were investigated by scanning electron microscopy, X-ray diffractometry and emission spectrum analysis. It can be concluded that the addition of l%Ga （molar fraction） reduces corrosion current density from 26.98 mA/cm^2 to 2.34 mA/cm^2; while the addition of l%Hg （molar fraction） increases corrosion current density. The addition of Ga and Hg both promotes the electrochemical activity of the alloys and the influence of Ga is more effective than Hg. Mg-5%Hg-l%Ga alloy has the best electrochemical activity, showing mean potential of-1.992 V. The activation mechanism of the magnesium alloy produced by Hg and Ga was put forward. Magnesium atoms are dissolved in liquid Hg and Ga to form amalgam and undergo severe oxidation at the amalgam/electrolyte interface.     

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.     

铁基牺牲阳极对17-4PH不锈钢的阴极保护

采用两种铁基牺牲阳极材料 (20CrMo和40CrMo) 对17-4PH不锈钢进行阴极保护,通过恒电流实验和自放电实验评估这两种牺牲阳极的保护效果,并用扫描电镜 (SEM) 和能谱 (EDS) 分析17-4PH阴极实验后的表面形态和元素成分。结果表明：两种牺牲阳极对17-4PH不锈钢均有500 mV左右的驱动电位。20CrMo牺牲阳极具有比40CrMo更负的工作电位、更大的电流效率,20CrMo牺牲阳极表面均匀腐蚀。经过20CrMo阳极保护的17-4PH阴极表面形成的氧化产物含量更少。20CrMo对17-4PH不锈钢的保护效果更好。     

凝固速度对Mg-2%Ga合金显微组织和电化学性能的影响(英文)

采用CALPHALD方法计算Mg-2%Ga合金的平衡凝固曲线。分别采用铁模和铜模冷却,用熔炼铸造法制备该合金,并用金相OM和扫描电镜SEM方法分析其显微组织,用恒电流法、动电位扫描和交流阻抗法测量不同冷速对Mg-2%Ga合金电化学性能的影响。结果表明:铜模冷却的Mg-2%Ga合金晶界存在尺寸小、数量多的Mg5Ga2化合物,其合金表面吸附了较少的 Mg+和氧化腐蚀产物,因此产生较低的腐蚀电流密度1.8×10-5mA/cm2。铁模冷却的 Mg-2%Ga合金在恒流100mA/cm2检测时具有更负的稳定电位-1.604V,这是由于铁模冷却产生较低冷却速度导致双电层具有较小的感抗和容抗时间常数,因此产生较短的活化时间和更好的电化学活性。     

Minor Ga addition to effectively inhibit PdSn4 growth between Sn solder and Pd substrate

PdSn₄ is the major reaction phase in the Sn-based or Sn–Ag–Cu solder joints with Pd substrate and it exhibits an extremely high growth rate. Ga is considered as a candidate alloying element in the Sn–Ag–Cu solders. This paper investigates the effects of Ga addition on the interfacial reactions between Pd and Sn–Ga (0.1wt.%–1wt.%Ga) solders by solid-state aging at 160, 180, and 200 °C and liquid-state aging at 250 °C. The most important finding is that minor Ga addition can effectively inhibit the fast PdSn₄ growth. In the solid-state reaction, with only 0.1wt.%Ga addition, the PdSn₄ growth was suppressed by ∼50%, compared with the pure Sn/Pd reaction. When the Ga content increased to 0.5wt.%, the PdSn₄ growth was further reduced by over 90%. In addition, a thin PdGa phase layer was formed at the interface between PdSn₄ and Pd, which was the main cause for the inhibition of PdSn₄ growth. The growth kinetics was systematically explored. The PdSn₄ growth had a higher activation energy for the higher Ga addition (>0.5wt.%). Furthermore, a similar reduction in the PdSn₄ growth was observed in the liquid-state reaction, but it was not as strong as in the solid-state reactions. The PdGa phase was not formed in the liquid-state reaction and the growth inhibition could be attributed to the Ga doping in the PdSn₄ lattice to retard the Sn diffusion.     

Pitting potential of high purity binary aluminium alloys—I. AlCu alloys. Pitting and intergranular corrosion

The effect of solute content on the pitting potential of Al-Cu alloys in 1M NaCl solutions was studied. In solution treated Al-Cu alloys the pitting potential of the alloy was found to increase with increasing Cu content. The maximum pitting potential value was limited by the solubility of Cu in the Al. It was found that, while the pitting potential of pure aluminium was ca. ?0.52 V, the pitting potential of Al-5.22% Cu was ?0.33 V.The ageing of the alloy affected the pitting potential. The pitting potential of the aged alloy was found to be determined by the copper content of the solute depleted zones formed during ageing. The formation of G.P. zones did not modify the pitting potential of the alloy. The formation of θ′′ phase, in an Al-3.5 Cu alloy, produced a decrease of 30 mV in the pitting potential, while the formation of θ′ phase produced a decrease of > 100 mV.As ageing was more rapid in the grain boundaries, there was a localized decrease in the pitting potential, which was followed by susceptibility of the alloy to intergranular corrosion.