Preparation of Mg-Yb alloy film by electrolysis in the molten LiCl-KCl-YbCl_3 system at low temperature

The electrochemical behavior of Yb3+ and electrodeposition of Mg-Yb alloy film at solid magnesium cathode in the molten LiCl-KCl-YbCl3(2 wt.%) system at 773 K was investigated.Transient electrochemical techniques,such as cyclic voltammetry,chronopotentiometry and chronoamperometry were used in order to explore the deposition mechanism of Yb.The reduction process of Yb3+ is stepwise reactions which are single-electron and double-electron reversible charge transfer reactions.The speed control step was a diffu...

Corrosion behavior of Cu-Ni-Ag-Al alloy anodes in aluminium electrolysis

The behavior of Cu-Ni-Ag-Al alloy used as anode for aluminum electrolysis was directly visualized in a two-compartment see-through cell during electrolysis, and its performances were tested at 850 ℃ in acidic electrolyte molten salts consisting of 39.3%NaF-43.7%AlF3-8%NaCl-5%CaF2-4%Al2O3 for 40 h in a laboratory cell. The results show that nascent oxygen oxidizes the anodic surface to form oxide film at the beginning of electrolysis. X-ray diffraction analysis of alloy surface show that the oxide film on the anodic surface consists of CuO, NiO, Al2O3, CuAl2O4 and NiAl2O4. However, SEM image shows the oxide film is porous, loose and easy to fall into electrolyte and to contaminate aluminum. The corrosion mechanism of metal anodes was analyzed.

Corrosion resistance of in-situ Mg-Al hydrotalcite conversion film on AZ31 magnesium alloy by one-step formation

In situ growth of nano-sized layered double hydroxides （LDH） conversion film on AZ31 alloy was synthesized by a urea hydrolysis method. The formation mechanism of the film was proposed. Firstly, the dissolved Mg2＋ ions deposited into a precursor film consisted of MgCO3 and Mgs（CO3）4（OH）2·4H2O; secondly, the precursor translated into the crystalline Mg（OH）2 in alkaline conditions; finally, the Mg2＋ ions in Mg（OH）z were replaced by A13＋ ions, Mg（OH）2 translated into the more stable LDH structure, simultaneously, the OH- ions in the interlayer were exchanged by CO32-, thus led to the formation of the LDH （Mg6Alz（OHh6CO3·4H2O） film. The results indicated that the LDH film characterized by interlocking plate-like nanostructures and ion-exchange ability significantly improved the corrosion resistance of the AZ31 Mg alloy.

Homogeneous CO_(3)O_(4) film electrode with enhanced oxygen evolution electrocatalysis via surface reduction

Homogeneous NaBH_(4)-reduced Co_(O)_(4) thin film electrodes with enhanced oxygen evolution electrocatalysis were obtained via a controlled-synthesis route.Firstly CoOx colloids were synthesized via ethylene glycol solvothermal method and cast on conductive glass substrates.The oxygen evolution reaction(OER) electrocatalysis of these asprepared CO_(3)O_(4) thin films were then significantly enhanced via a simple surface reduction by NaBH_(4) solution.The OER catalytic performance of the NaBH_(4)-reduced thin films was strongly dependent on the NaBH_(4) concentration.The use of NaBH_(4)-reduced thin film electrodes for OER in alkaline solution supported higher current density and consequently negative shifts of the onset potential compared to that of the pristine.The optimal B_(12.5,20)-CO_(3)O_(4) thin films exhibited excellent OER catalytic performances:At the current density of 10 mA·cm^(-2),a low overpotential of 365 mV and a small Tafel slope of 59.0 mV·dec^(-1) were observed.In addition,these B_(12.5,20)-CO_(3)O_(4) thin film electrodes possessed good stability that can well recover its OER performance in a 24-h chronoamperometric stability test.

Electrochemical Behavior of Oxide Films of Stainless Steel in 40 kHz Sonicated Sulphate Electrolytes

This paper describes effects of 40 kHz ultrasound on the oxide films of stainless steel in sulphate electrolytes so as to determine the transmitted power and to characterize mass transfer and peak current density on the electrode surface. Emphasis was mainly laid on electrochemical oxidations and peeling mechanism of oxide films in sonicated sulphate solutions （0.5 and 1.0 mol/L）. Polarization voltammetry, current response traces and SEM analysis were carded out in order to provide full information as to oxide films surface. Results shows that the rate of electrochemical oxidation, the shape of polarization curves and the surface micrographs in sonicated sulphate electrolytes are different from those obtained without introduction of ultrasound. It is concluded that ultrasound can change the electro-chemical behavior of oxide films by its cavitaion effects, which would produce transient mechanical impulsive force and enhance electrochemical reactions.

基于干膜掩模的群柱体织构电解加工技术研究

微织构广泛运用于摩擦磨损、热能交换、关键零/部件密封和生物医学等众多领域,柱体织构作为微织构的一种,其在增摩方面起到至关重要的作用。利用电解加工效率高、无残余应力等优势,提出了一种基于干膜掩模电解加工群柱体织构的方法。选用了高黏附性的MS系列干膜制备掩模板,进行流场、电场和稀物质传递的多物理场耦合分析,研究了不同模板厚度对加工区域电解液流速、气泡率以及电导率的影响。分析结果表明,50μm厚度的模板能够带来工件表面更高的电解液流速,加快产物及气泡的排出,工件表面的电导率更高。通过试验研究了加工电压、加工时间和脉冲占空比对群柱体织构尺寸的影响。试验结果表明,在加工电压为25 V、加工时间为15 s的条件下,可以获得定域性较好的群柱体织构;此外,脉冲电解加工时,在脉冲占空比为20%、脉冲频率为4 kHz的条件下,不溶性电解产物、气泡及电解液的传质过程得到进一步改善;最后,在加工电压为25 V、加工时间为15 s、脉冲占空比为20%和脉冲频率为4 kHz的优选加工参数下,在TC4表面加工出直径为320.48μm、高度为15.06μm以及侧向腐蚀系数EF=1的群柱体织构阵列。

Incubation of PbSe Thin Films in a Tin(Ⅱ) Salt Aqueous Solution:Modification and Ion-Exchange Reactions

Topochemical ion-exchange reactions between solid micro- and nanostructured metal chalcogenides and aqueous salt solutions are generally used for formation of composite structures based on initial metal chalcogenides and products of their ion-exchange transformation. However, ion exchange has promises as a route to obtaining both composites and solid solutions based on the initial and the end chalcogenide phases. With the help of the ion-exchange technique, single-phase films of Phi xSnxSe substitutional solid solutions with a tin content up to -2 at.%, which are promising for mid- and long-wavelength infrared radiation （IR） optoelectronics, have been obtained at the interface between PbSe poly- crystalline thin films and SnCl2 aqueous solutions containing sodium citrate. It has been shown that the pH value and temperature of the reaction system play an important role in the ion-exchange process. Incubation of lead selenide （PbSe） films in a tin（II） salt aqueous solution also leads to their modification with oxygen-containing tin compounds to a depth of-3 nm. Differences in the film structure, such as changes in the coherent scattering region sizes and orientation of crystallites along the [220] direction, which arise during the contact with citrate-containing SnCl2 solutions, have also been revealed. For the first time, an idea of the existence of a relatively wide reaction zone of an intragranular topochemical ion-exchange reaction in an aqueous solution, within which substitutional solid solutions can form in micro- and nanostructured systems, has been set forth.

铝合金阳极氧化膜上阴极电解沉积的稀土铈转化膜

通过阴极电解的方法在铝合金多孔阳极氧化膜上沉积了富铈转化膜 .电解成膜溶液为含1g/LCeCl3 ·7H2 O和 10ml/LH2 O2 的水溶液 .用XPS、FEM、XRD、和EDAX等分析手段对此种转化膜的组成、结构形貌进行了研究 .结果表明 :这种铈转化膜的微结构与氧化膜的多孔结构紧密相关 ,并且随电解时间和电流密度的改变而逐渐变化 ;转化膜主要由三价铈化合物组成 ,阴极电解 1h后膜厚约 14 0nm ,并呈非晶态特征 .

水稻白叶枯病菌生理小种在纳米银膜上的表面增强拉曼光谱初探

用硝酸银和聚乙烯醇混合溶液作为电解液,把载玻片放入电解液中,用银棒作为电极在直流电压下电解1 h,使载玻片在电解出的银胶中静置12 h后,取出晾干,即得制备的银膜。用便携式拉曼光谱仪测得在银膜上的白叶枯病菌7个生理小种的表面增强拉曼光谱(SERS)。7个生理小种分别是1-YN1,2-YN7,3-YN11,4-GD414,5-SCYC6,6-HEN11,7-FWJ,7个生理小种的SERS谱在峰位及峰的相对强度上都有很多差别。这可用于生理小种的鉴别。因为银膜上的纳米银颗粒是银胶中银颗粒的聚合体,这种聚合体大大缩小了纳米银之间的距离,从而产生了很强的电磁增强作用。电解法制备的银膜价格低廉,增强效果好,普通实验室便可以制备。此研究为快速、方便检测白叶枯病菌不同生理小种提出了一种新的方法,对白叶枯病的防治具有重要的意义。

不锈钢表面高温热处理氧化皮的常温去除机理研究

在高温使用环境或热处理中,不锈钢表面容易形成氧化皮,影响了不锈钢零件的应用。利用超声电化学方法去除不锈钢表面的高温热处理氧化皮,即在超声波的辅助作用下,电解不锈钢表面氧化皮,并研究了电解和超声波对氧化皮去除作用规律。试验结果表明:辅以超声波作用的电化学技术可以在常温下快速去除不锈钢表面的高温热处理致密氧化皮,恢复了不锈钢的金属色泽表面。超声波不仅可以对不锈钢表面氧化皮产生力学效应,而且可以明显加快电化学阳极反应速率和氧化皮的脱落速度。

湿法冶金新技术进展

概述了矿浆电解、生物冶金、膜分离技术和机械活化浸出等几种湿法冶金新技术 ,并介绍了其应用领域和发展方向。

利用导电涂膜直接电解海水法防护生物腐蚀 1.模拟和测量技术

基于电化 学微探针 和微弱 信号检测 技术， 采用 四电 极体 系、双恒 电 位仪、锁相 相 关测定系统 以及三维 微调装 置建立模 拟和测量 系统，将 首次实 现对利 用导 电涂 膜直 接电 解海 水法 防护生物腐 蚀中微 米尺度内 痕量 Ｃｌ Ｏ － 浓度 的测量．本 文报道 了模拟和 测量实验 的阶段 性进展．

SO_4^(2-)/TiO_2固体超强酸掺杂可剥离膜的放射性去污性研究

制备出酸度- 13. 20 <H0 < - 11. 99 的SO42 /TiO2 固体超强酸,将其掺杂于导电高分子聚苯胺后制备出应用于核设施工业的放射性去污可剥离膜,得到满意的结果是其电导率达到7.01S/cm,涂膜湿法电解的放射性去污率高于94%,涂膜干法电解去污率高于97%。

催化铁内电解/生物膜法处理化工废水

化工废水因含有难降解和对生物有抑制性的物质而较难处理,为此以某工业区的化工废水为研究对象,考察了催化铁内电解/悬浮填料生物膜法的处理效果,并同现有工艺进行比较。结果表明,催化铁内电解可提高废水的可生化性,整个工艺对COD、BOD5、NH3-N、色度等的去除效果较现有工艺有明显改善。

用阴极电解法沉积铝合金铈转化膜

在铈盐溶液中用阴极电解的方法沉积铝合金铈转化膜，用电化学测试、腐蚀实验、ＳＥＭ和ＥＤＡＸ等分析手段研究了转化膜的性能．结果表明，铈转化膜的形貌组成和耐蚀性能与铝合金表面状态和阴极是否发生析氢反应关系密切，要想获得性能良好的铈转化膜必须抑制氢气在阴极上的析出．

ELID镜面磨削中砂轮生成氧化膜特性及其作用的研究

研究砂轮电解氧化膜的粘附强度、硬度、致密性、导电性和生成速度等物理特性与砂轮结合剂成分、磨削液成分和电解参数的关系，并分析氧化膜在ＥＬＩＤ磨削中的作用。

氯霉素在电解法制备纳米银膜上的表面增强拉曼光谱的研究

用电解法制备了一种纳米银膜,并用扫描电镜和透射电镜进行了研究。我们得到了银膜上的氯霉素的SERS谱,并且用gaussian’98软件对氯霉素的Raman谱进行了运算,发现实验结果和理论计算结果有很好的相似性。本实验说明电解法制备的纳米银膜对于检测氯霉素有很好的应用前景。

电化学法预处理硅基片提高金刚石成核密度的研究

通过用电化学法预先沉积一层碳膜的方法，利用热丝化学汽相沉积法使金刚石在光滑硅片上的成核密度达到１０７ｃｍ－２左右，与未镀碳膜相比提高了近３个数量级。文中还分析了可能的原因。

304不锈钢Na_2SO_4电解酸洗工艺的研究

在分析Na2SO4电解酸洗机理的基础上,试验研究了电解酸洗的影响因素(如电流密度、电解液质量分数和电解液温度),并提出热轧304带钢最优电解酸洗工艺。试验结果表明,采用质量分数15%、温度75℃的Na2SO4溶液,电流密度0.04 A/m2,阳极处理时间10 s,阴极处理时间为阳极时间2倍的电解工艺,可有效去除304不锈钢表面的氧化皮。

2024铝合金阳极氧化、电解着黑色工艺优化及膜的性能

为了在2024铝合金表面获得结合力好、耐候性好及黑色纯正的阳极氧化膜,首先在硫酸电解液中对2024铝合金进行阳极氧化,之后在Sn-Ni-Cu-Co电解液中进行电解着黑色,采用SEM,XRD,EDS分析膜层的表面形貌、截面特征、成分及膜中的元素分布,优选了阳极氧化、电解着色电解液的成分;从金属颗粒沉积、氧化还原方面分析了电解着色的机理。结果表明:最佳阳极氧化液配方为100.0 g/L H2SO4,5.0 g/L H3BO3,2.0 g/L(NH4)2SO4,2.0 g/L苹果酸,2.0 g/L MgSO4,1.5 g/L Al2(SO4)3;最佳着色液配方为15 g/L SnSO4,10 g/L NiSO4,10 g/L CuSO4,10 g/L C4H6O4Co,3 g/L FeSO4;在Sn-Ni-Cu-Co电解着色液中,Sn2+,Co2+,Cu2+等通过还原反应以单质的形式沉积于氧化膜层的孔隙或底部,通过多重散射使氧化膜颜色加深,从而得到了黑色的氧化膜;最佳氧化膜颜色为石墨黑,结合力及耐候性均较好。