大塑性变形对镁合金微观组织与性能的影响

综述了在镁合金加工中得到应用的大塑性变形方法,针对性地分析了不同制备工艺对合金晶粒尺寸、织构、性能的影响,提出了今后大塑性变形在镁合金加工中的研究重点是:优化现有加工工艺;发挥细化晶粒的作用;控制合金织构;提高合金的综合性能.     

制备条件对纳米镍粉电化学性能的影响

在水、乙二醇和1,2丙-二醇3种溶液中,以NiSO4.6H2O为主盐、水合肼为还原剂制备纳米镍粉,然后将镍粉压制成片状电极。采用X射线衍射分析镍粉的成分,SEM和TEM表征其微观形貌,XPS研究片状镍电极表面的化学状态,并在碱性溶液中进行循环伏安测试。结果表明:纳米镍粉的制备条件对其电化学性能存在明显的影响,在乙二醇溶液中制得的镍粉呈分散状态,且颗粒尺寸分布均匀,直径为30~100 nm,较在其它两种溶液中制备的镍粉电极具有更高的氧化还原电流密度,即具有更高的电化学活性。     

快速退火对冷轧超低碳钢组织和性能的影响

采用OM、SEM、EBSD和单轴拉伸方法,从某冷轧超低碳钢的显微组织、晶粒尺寸分布、晶粒取向和力学性能4个方面对比分析了常规退火工艺(低温长时间)与快速退火工艺(高温瞬时)。结果表明,冷轧超低碳试验钢在650℃快速退火15 s时,屈服强度和抗拉强度分别为445.38 MPa和494.07 MPa,相比常规退火试样性能(屈服强度为274.35 MPa,抗拉强度为388.99 MPa)得到明显提升,同时还保证了24.7%的伸长率。造成常规退火与快速退火试样性能差异的主要原因是晶粒细化与典型的γ取向,其中晶粒细化占主导地位。快速退火具有明显的细晶强化作用,但同时恶化加工硬化能力,从而导致伸长率下降。快速退火会抑制第二相颗粒的析出,且细化第二相颗粒。快速退火试样呈典型的γ取向,更有利于提高轧向性能,但常规退火试样为近γ取向,所以取向的影响较小。     

合金元素对Mg-Ni电极电化学性能的影响

综述了合金元素对Mg-Ni基电极电化学性能的影响，特别是对Mg-Ni型储氢合金电极的放电容量和循环寿命的影响，并提出了一些改进办法。     

累积叠轧温度对AZ31镁合金组织和性能的影响

通过光学显微镜、室温拉伸试验、显微硬度计、X射线衍射仪、扫描电镜等方法研究了累积叠轧温度对AZ31镁合金晶粒尺寸、基面织构、界面结合情况及力学性能的影响。结果表明:3道次累积叠轧后的AZ31镁合金晶粒细化效果明显,硬度增大,随着累积叠轧温度的升高,晶粒细化效果减弱,硬度增加趋势减弱。累积叠轧温度升高有弱化基面织构的作用。AZ31镁合板材在450 ℃累积叠轧3道次,综合力学性能最佳,为显微硬度70.64 HV0.05,抗拉强度288.64 MPa,屈服强度203.76 MPa,伸长率16.96%,界面结合强度21.53 MPa。     

Ni对V基合金电极材料电化学性能的影响

钒基复合材料V-Ti-Cr-Fe作为气态贮氢合金,其吸放氢容量很大.常压下其吸放氢平台很低.在此基础上用Ni替代Ti或Cr元素,进行电弧熔炼法形成多元合金,可优化出一种具有较好贮氢性能的合金作为电极材料.实验表明,用Ni代替其中的Ti或Cr对改性后的V基储氢合金的放电容量有不同程度的提高.当不含Ni时,它基本上没有放电量;Ni的摩尔分数x=0.1时,其放电容量可达到190.7mAh/g.具有良好的电化学循环稳定性;当循环次数达100次时,它的容量保持率达99%以上,并有效地提高了电催化活性,降低了合金的阻抗.     

钛基材上制备TiO2纳米管阵列电极的电化学性能

在0.5%(质量分数)NH4F/甘油电解液中通过恒压阳极氧化法在钛基体上制备TiO2纳米管阵列.采用循环伏安法、紫外-可见吸收光谱、顺磁共振波谱仪和傅立叶红外谱对TiO2纳米管阵列的表面性能进行了表征.结果表明:TiO2纳米管阵列电极可发生两个光化学过程,测得的电化学激发能?EOH/?OH＞1.643 V,对应的吸收光波长λ＜853 nm;TiO2纳米管阵列电极光化学性能变化是由于在电极表面发生Ti3+与Ti4+转化的过程中形成了·OH.     

合金元素对Mg-Ni电极电化学性能的影响

综述了合金元素对Mg-Ni合金系电极电化学性能的影响，特别是对Mg-Ni型储氢合金电极的放电容量和循环寿命的影响，并提出了一些改进方法。     

不同Ti基复合电极材料的电化学性能研究

目的制备具有良好电催化活性和耐腐蚀性能的Ti/Pb-WC-PANI复合材料,用作锌电积过程中的电极材料,达到降低能耗的目的。方法在Ti基上采用脉冲电沉积法,以纯铅作为打底层,再沉积Pb-WC-PANI。通过对脉冲Pb-WC-PANI复合镀层、直流Pb-WC-PANI复合镀层、铅银合金以及纯铅的稳态极化曲线、循环伏安曲线和电化学阻抗谱的对比分析,研究其析氧电催化活性,利用塔菲尔曲线研究其腐蚀性能。结果在电流密度2 A/dm~2,正向导通时间0.3 ms,周期1.5 ms,工作时间200 ms,磁力搅拌,25℃施镀1.5 h的工艺条件下制备铅底层,再在脉冲平均电流密度2 A/dm~2,脉宽0.3~0.5 ms,脉冲周期1.5 ms,25℃沉积1 h的工艺条件下镀Pb-WC-PANI,得到Ti/Pb-WC-PANI复合材料。其开始析氧电位最低,在1.7 V左右,伏安电荷q~*=0.54 C/cm~2,腐蚀电位E_(corr)=-0.530 V(vs.SCE),腐蚀电流密度J_(corr)=6.90×10~(-4) A/cm~2。结论脉冲镀Pb-WC-PANI复合材料可以有效地降低析氧电位,其伏安电荷最大,并且反应阻抗较低,表面的电催化活性最好。同时,其腐蚀电位最高,腐蚀电流密度最低,耐腐蚀性能最好,在锌电积模拟溶液中具有良好的综合性能。     

AZ31镁合金晶粒细化对其力学性能的影响

搜集了大量国内外有关AZ31镁合金经过不同加工工艺后不同晶粒尺寸所对应的力学性能的文献资料,对它们的分析研究表明,加工工艺的不同、晶粒细化到一定程度变形机制的改变、织构的软化及晶界参与滑移的影响,在一定条件下合金晶粒的细化并不能提高AZ31镁合金的强度性能。     

The effect of additives on the corrosion resistance of Zn electrode in alkaline battery system

Zn electrodes are widely used as an anode material in alkaline battery systems in highly concentrated KOH electrolyte. However, it is well known that their life cycle is significantly shortened due to dendrite growth caused by high dissolution and rapid electrochemical reaction. In this study, additives such as Ca(OH)_￡σ, citrate, tartrate, and gluconate were added to 40% KOH electrolyte solution at 25 and 5 wt.% Pb₃O₄ was mixed with the Zn electrode. The effects of both Pb₃O₄ and the additives on the electrochemical behavior of the Zn electrode were investigated through corrosion potential measurements, potentiodynamic polarization curves, cyclic voltammetry, and SEM photographs. The addition of Pb₃O₄ had a considerable effect on decreasing the corrosion rate of the Zn electrode, and the corrosion potential of the Zn electrode with Pb₃O₄ addition shifted to a more positive potential than that of a pure Zn electrode. However, upon addition of other additives, the corrosion potential was slightly shifted to the negative direction again. The addition of 4 kinds of additives appeared to play an important role in improving the corrosion resistance. Moreover, among the four additives, tartrate displayed a relatively good effect in terms of increasing the corrosion resistance as well as improving the discharging characteristics among.     

Effect of current density on the corrosion protection performance of polyaniline coated AISI 4140 steel

The present work reports on electropolymerisation of aniline onto AISI 4140 steel substrate at room temperature in oxalic acid media by the potentiodynamic electrodeposition method. The effect of coating current density on the morphology of conductive polymer films and their corrosion behaviour has been investigated. The electrolyte solution comprised 0.1 M aniline?+?0.3 M oxalic acid. The effects of deposition current density changes (0.1, 0.2, 0.3, 0.4 and 0.5?mA cm^?2) on the films were investigated. The PANI film was characterised using cyclic voltammetry and optical microscopy; it was covered with a dark green-yellow homopolymer film of strongly adherent homogeneous characteristic. The corrosion behaviour of steel electrodes with and without polyaniline (PANI) film in 3.5 wt-% NaCl solution was investigated through anodic polarisation curves. The results indicated that the PANI coating obtained under 0.2?mA cm^?2 was the most corrosion protective.     

Effects of surface modification on electrochemical performance of MnO2

The MnO2 samples coated with Ca（OH）2 were prepared by a liquid-phase surface treatment method. The physical properties of the samples were examined by SEM, EDAX and chemical analysis, and their electrochemical performances were investigated by means of galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy （EIS）. The SEM results show that the samples coated with Ca（OH）2 display a porous surface structure. The electrochemical experiments indicate that the surface modification decreases the polarization of MnO2 electrodes and improves their discharge potentials and discharge capacities.     

Electrochemical behavior of corroded and protected construction steel in cement extract

The corrosion behavior of corroded, cathodically protected and control (reference) construction steel, previously embedded in concrete, was studied in cement extract (pH 12.6, considered as concrete pore water), using cyclic voltammetry (CVA) and potentiodynamic polarization (PDP). The necessity for this investigation occurred from the previously observed and commented discrepancies in the recorded corrosion parameters for corroded and protected steel in embedded conditions 1 . Therefore this study aimed to evaluate how the “naturally” formed in concrete product layers (after 460 days) will influence the electrochemical behavior of the steel in cement extract. The PDP measurements reveal the lowest corrosion resistance to be for the previously corroded steel samples, for which the most active corrosion potential (?0.7 V SCE) and the highest anodic current in the potential region 0 to 0.6 V (SCE) were recorded. The CVA tests support the results from PDP and correlate the properties of the naturally formed layers with the recorded peak current densities and peak potentials with cycling. For all specimens, except the corroded ones, the peak potential initially shifts anodically, which denotes for a high corrosion resistance in the former and low corrosion resistance in the latter case. For the control and protected specimens, the passive current in the potential region of 0 to 0.6 V (SCE) remains almost unchanged with cycling, i.e. the protective properties of the initial layers remain unchanged. Thickening of the film with cycling does not influence the corrosion resistance of the previously formed layers. For the protected specimens, however, a tendency to reach a steady state and change of peak currents' height only were observed, without a pronounced shift to more anodic values. An increase in the peak current only, not accompanied by anodic shift of the peak potential, suggests that the layers in the cathodically protected specimens are more homogeneous and compact. Overall it can be stated that in cement extract, the product layer with lowest corrosion resistance is the one on the surface of the corroded steel reinforcement. The product layers in the protected specimens (although similar to control conditions) are with the highest corrosion resistance.     

热镀铝锌硅产品耐腐蚀性能研究及工艺优化

针对热镀铝锌硅产品,采用了中性盐雾试验,结合SEM微观分析等手段,研究了产品耐腐蚀性能;分析了产品表面点状及线状缺陷的形成原因,其分别由锌灰缺陷及针孔漏镀缺陷而导致。为此,提出了相应的工艺优化措施,减少了产品表面缺陷,有效提高了镀铝锌硅产品的耐腐蚀性。     

聚苯胺对锌电积用复合惰性阳极材料电化学性能的影响(英文)

为了寻找一种可以替代锌电积用 Pb-Ag 合金的阳极材料,通过 PANI(聚苯胺)、WC(碳化钨)颗粒与 Pb2+的双脉冲电沉积,在 Al 合金基体上制备了 Al/Pb-PANI-WC 复合惰性阳极材料。测试了镀液中不同 PANI 浓度下制备的惰性阳极材料的阳极极化曲线、循环伏安曲线和塔菲尔极化曲线,采用扫描电镜考察复合惰性阳极材料的微观组织特征。结果表明:当将制备镀液中 PANI 浓度控制在 20 g/L 时,Al/Pb-PANI-WC 复合惰性阳极材料的微观组织和成分分布均匀,在含 50 g/L Zn2+、150 g/L H2SO4的 35 °C锌电积液中具有较高的电催化活性、较好的电极反应可逆性和耐腐蚀性,在电流密度 500 A/m2和 1000 A/m2下的析氧过电位与 Pb-1%Ag 合金相比分别降低了 185 mV 和 166 mV。     

银铜箔轧制用银铜板的退火组织与性能

采用光学显微镜、电子背散射衍射技术、维氏硬度计和电化学工作站等研究了轧制银铜板在退火过程中的组织、织构演变规律及其对维氏硬度、耐腐蚀性能的影响。结果表明:轧制银铜板退火时,晶粒形态由轧态的长条状演变为等轴晶组织,且平均晶粒尺寸增大,织构类型由铜型织构、黄铜型织构、S织构和R织构等形变织构演变为立方织构和{025}<001>等退火织构;随退火温度的升高,银铜板维氏硬度减小,银铜板小角度晶界含量降低,∑3晶界含量升高,耐腐蚀性能先减弱后增强。银铜板在300 ℃保温10 min时,立方织构含量最多,硬度为60 HV0.3,耐腐蚀性能较好。     

微量Ti对Mg-9Al合金显微组织和性能的影响

研究了微量Ti对Mg-9Al二元合金铸造显微组织和性能的影响.研究发现,Ti的加入,使得Mg-9Al合金的塑性增加,明显提高了Mg-9Al合金的抗腐蚀性能.分析结果表明,残留Ti弥散分布在合金的基体中,Ti的加入有效降低了Fe的含量,一定程度上“净化”了合金液,抑制了合金凝固时的异质形核,使组织晶粒粗化.实验发现,炉前加入0.12%的Ti(质量分数,下同)时,Mg-9Al合金的晶粒大小由145μm增大到188μm.随着Ti的加入,Mg-9Al铸造组织中β相的形态,由半连续骨骼网状改变为短条状和颗粒状.当炉前加入0.12%的Ti时,Mg-9Al合金的综合性能较佳.     

不锈钢表面电接枝聚苯胺的防腐性研究

用循环伏安法在不锈钢上制备出聚苯胺膜,并研究修饰剂(有机硅烷偶联剂KH-560)对聚苯胺成膜的影响;用扫描电子显微镜、红外光谱和电化学方法研究聚苯胺的微观结构及电化学性能.结果表明,经修饰后的聚苯胺膜使不锈钢的腐蚀电位提高了70 mV,腐蚀电流由1×106A下降到6.3×10-8A,大幅度提高不锈钢的抗腐蚀性能.     

晶粒度对塑料模具钢性能的影响

采用光学轮廓仪、光学显微镜以及扫描电镜等研究了晶粒度对镜面塑料模具钢力学性能、抛光性能和腐蚀性能的影响。结果显示,晶粒度为6级时经成分优化后的XPM钢具有良好的强韧性配合,抗拉强度为1250 MPa,断面收缩率为24.5%,伸长率为20.2%,冲击吸收能量为24.8 J;XPM钢各晶粒度级别的Ra值均在5~6 nm之间;随着晶粒度级别的增大,腐蚀速率逐渐减小。