亚铁离子对甲磺酸高速镀锡溶液电化学行为及其镀层的影响

研究了带钢甲磺酸体系高速镀锡工艺中,杂质Fe2+对镀锡溶液电化学行为及其镀层的影响。镀液循环伏安特性和调制动力学行为研究结果表明:Fe2+主要对甲磺酸镀锡液的阴极放电过程有影响,提高了镀液的析氢活性,降低了电流效率,Fe2+在H+和Sn2+的放电过程中不参与沉积。转速1 000 r/min、Fe2+含量大于5 g/L时,Sn2+电化学反应扩散控制拐点消失,H+和Sn2+的混合反应控制区增宽,析氢电位随转速提高而正移。赫尔槽试验和扫描电镜观察发现:Fe2+不影响镀液的分散能力,但降低了镀液电流效率;Fe2+含量大于15 g/L时,1.1 g/m2锡量的镀锡板的镀层表面粗糙,结晶不均匀细致,Fe2+的存在使镀层孔洞明显增加,镀锡板耐蚀性下降。     

粉煤灰对镀锡液中金属离子的吸附研究

在镀锡液中,经常由于有杂质铁离子的存在而使镀液的效能下降。使用粉煤灰作为吸附剂,研究了粉煤灰对含有Fe2+、Sn2+溶液中的金属离子的吸附规律。实验使用邻菲罗啉吸光光度法对镀锡液中的Fe2+进行了测定,使用碘量法对Sn2+进行标定。研究结果表明,10 g/L粉煤灰,粒径为33~55μm,θ为50℃时对Sn2+的吸附量最小,对Fe2+的吸附量接近最大值。     

镀液中Sb(Ⅲ)与 Ce(Ⅲ)盐对锡镀层结构缺陷和可焊性的影响

根据镀层元素分析结果,证实电镀时 Sb 与 Sn 发生共沉积而 Ce 与 Sn 不发生共沉积。应用正电子湮没平均寿命τ对镀层结构残缺程度进行评估,表明 Sb 含量为0.1～0.5 wt.%的 Sn-Sb 镀层结构缺陷较少,可焊性较好。实验还表明镀液中 Ce~(3+)的作用在于阻化 Sn~(2+)的水解和氧化,使镀液稳定,因而减少锡镀层结构缺陷,改善了可焊性。镀液中合适的 Ce~(3+)浓度范围为1.5～6.0g/L。     

PAM对热镀锌助镀液中铁离子去除效果研究

热镀锌助镀液中铁离子含量过高会严重影响镀层质量。本文采用化学沉淀法处理热镀锌助镀液原水中过量的铁离子。采用双氧水氧化法氧化水样中的Fe~(2+)离子,调节pH到4. 5~5. 0,使铁离子生成Fe(OH)3沉淀,分别加入不同类型的聚丙烯酰胺(PAM)絮凝。结果表明:投加过氧化氢15 m L/L时对水样中的Fe~(2+)离子氧化效果最好,离子度为40的阳离子型PAM在浓度为0. 06 g/L时对氢氧化铁的絮凝效果最好,絮体粒径为67. 3μm,铁离子去除效率为95. 4%。     

甲基磺酸盐镀锡稳定剂的研究

在含有Sn2+90 g/L,甲基磺酸120g/L、OP乳化剂10 mL/L、光亮剂12 mL/L的基础镀锡液中,通过加速氧化实验,确定了最佳稳定剂组成为:抗坏血酸2 g/,三氯化钛0.1 g/.结果表明,稳定剂与光亮剂具有协同作用,稳定剂使镀液的分散能力、光亮电流密度范围、锡析出过电位略有提高,电流效率提高1.14%以...     

真空浓缩冷却结晶法减少弗洛斯坦镀锡液中的亚铁离子

采用真空浓缩冷却结晶法去除镀锡液中的Fe2+,考察了镀锡液初始Fe2+含量、体积浓缩程度、冷却结晶温度和时间对Fe2+去除率和Sn2+损失率的影响。结果表明,初始Fe2+含量越高,浓缩程度越大,冷却结晶时间越长、冷却结晶温度越低,Fe2+的去除率就越高,并且相应的Sn2+损失率都远低于Fe2+去除率。真空浓缩的最佳工艺条件为:真空度0.097~0.098 MPa,温度50°C,体积浓缩程度60%。冷却结晶的最优工艺条件为:温度5°C,时间2 h。Fe2+含量为13.44 g/L、Sn2+含量为30.30 g/L的镀锡液在该条件下处理后,Fe2+的去除率达79.73%,Sn2+损失率为39.48%。将该处理液按正常Sn2+含量(25~30 g/L)稀释后,Fe2+含量为4.46 g/L,满足镀锡液中Fe2+含量应低于7 g/L的要求。     

添加剂对无氰电镀铜-锡合金(低锡)镀层性能的影响

通过赫尔槽试验与直流电解试验,研究了添加剂在焦磷酸盐溶液体系无氰电镀铜-锡合金(低锡)工艺中的作用。该体系镀液组成与工艺条件为:Cu2P2O7·3H2O25g/L,Sn2P2O71.0g/L,K4P2O7·3H2O250g/L,K2HPO4·3H2O60g/L,温度25℃,pH8.5,电流密度1.0A/dm2。采用扫描电镜(SEM)、X射线衍射(XRD)、能谱(EDS)、中性盐雾试验等方法研究了添加剂对镀层组成结构、外观、耐腐蚀性能及微观形貌的影响。结果表明,焦磷酸盐溶液体系无氰电镀铜-锡合金(低锡)时使用有机胺类添加剂可抑制Sn的析出,使合金镀层致密均匀,耐蚀性能好。镀层结晶主要为Cu13.7Sn结构,镀层中Sn含量为9%～11%。镀液中添加剂的使用量增加,则合金镀层中的Sn含量降低。     

重铬酸钾滴定法测定甲基磺酸锡中Sn~(2+)和Sn~(4+)的含量

研究了以重铬酸钾间接滴定甲基磺酸锡中Sn2+和Sn4+含量的方法。在6mol/L盐酸中用锌粉把Sn4+还原为Sn2+,加入硫酸铁铵快速氧化Sn2+,硫酸铁铵中的Fe3+被还原为Fe2+。用重铬酸钾滴定Fe2+来间接测定Sn2+和Sn4+含量。方法相对标准偏差为1.65‰,回收率99.98%。该方法简便,快速,结果准确可靠。     

添加剂对锡–银–铜共沉积的影响

通过测定循环伏安曲线、镀层表面形貌和X射线衍射谱图,研究了单一的烷基糖苷(APG)或APG+槲皮素的组合添加剂对Sn–Ag–Cu三元合金共沉积的影响。镀液的基础组成和工艺条件为:Sn(CH3SO3)20.18 mol/L,Ag2O 0.006 mol/L,Cu(CH3SO3)20.001 2 mol/L,硫脲0.06 mol/L,羧乙基乙二胺三乙酸(HEDTA)1.0 mol/L,pH 5.0,温度25°C,电流密度6.6 mA/cm2,时间30 min。结果表明,镀液中APG或APG+槲皮素的存在使锡离子的扩散系数减小,Sn–Ag–Cu三元合金的共沉积过程受阻。镀液中加入1.00 g/L APG或1.00 g/L APG+0.05 g/L槲皮素后,Sn–Ag–Cu镀层外观改善,镀层结晶细致、均匀,晶面择优取向由Sn(211)转变为Sn(200)。因此,APG或APG与少量槲皮素的组合适合用作Sn–Ag–Cu共沉积的添加剂。     

低温镀铁电解液氧化和水解

1前言镀铁层的形成是由亚铁离子在被镇表面上放电沉积的、镀铁电解液亚铁离子的氧化起因有三：一是空气氧化，特别是电镀液表面层亚铁离子的氧化；二是阳极析出的[O]以及形成的O2的氧化；三是在阴极区附近的高pH区域内加速Fe2+离子的氧化，氧化速度为：2实验结果与讨论取300mlFeCl2·4H2O电解液（300g/L）平均分到三个烧坏中，分别调pH值为0.9、1.4和2.1、在常温下自然氧化，每24h测一次Fe3+浓度，绘出Fe3+浓度－时间曲线（略）．pH值为0对电镀液，Fe’“自然增长速度为0．Zg／24h左右，经220h后＆e’”浓度达249见时开始发生水解，电…     

Conductivity and ion transport in silver—tin pyrophosphate baths

Mass transfer of metal ions and a pyrophosphate ion in silver—tin pyrophosphate baths was studied. The complex ion, [Sn₂(P₂O₇)₂]^6?, is formed in a solution of pH greater than 9.7 with a pyrophosphate to Sn²⁺ ratio of 2:1. The pyrophosphate ion simultaneously functions for enhancing conductivity as a complexing agent to promote the codeposition of silver. The diffusion coefficients of [Ag(CN)₂]^? and [Sn₂(P₂O₇)₂]^? were 1.39 × 10^?5 and 7.87 × 10^?6 cm² s^?1, respectively, but that of [Sn₂(P₂O₇)₂]^6? become larger as the pyrophosphate concentration was increased. The apparent activation energy of diffusion of [Ag(CN)₂]^? was 3.1 kcal mol^?1 and that of [Sn₂(P₂O₇)₂]^6? was 2.7 kcal mol^?1.     

Advanced structures in electrodeposited tin base anodes for lithium ion batteries

A novel composite anode material consisted of electrodeposited Sn dispersing in a conductive micro-porous carbon membrane, which was directly coated on Cu current collector, was investigated. The composite material was prepared by: (1) casting a polyacrylonitrile (PAN)/dimethylformamide (DMF) solution that contained silica particles on a copper foil, (2) removing the solvent by evaporation, (3) dissolving the silica particles by immersing the copper foil into an alkaline solution, (4) drying the copper foil coated by micro-porous membrane, (5) electrodepositing Sn onto the copper foil through the micro-pores in the micro-porous membrane, and (6) annealing as-obtained composite material. This method provided the composite material with high decentralization of Sn and supporting medium purpose of conductive carbon membrane deriving from pyrolysis of PAN. SEM, XRD and EDS analysis confirmed this structure. The characteristic structure was beneficial to inhibit the aggregation between Sn micro-particles, to relax the volume expansion during cycling, and to improve the cycleability of electrode. Galvanostatic tests indicated the discharge capacity of the composite material remained over 550 mAh g⁻¹ and 71.4% of charge retention after 30 cycles, while that of the electrode prepared by electrodepositing Sn on a bare Cu foil decreased seriously to 82.5 mAh g⁻¹ and 13%. These results show that the composite material is a promising anode material with larger specific capacity and long cycle life for lithium ion batteries.     

Synthesis, ion exchange properties and applications of tin(IV) antimonoarsenate

Crystalline (c-SnSbAs) and amorphous (a-SnSbAs) samples of tin(IV) antimonoarsenate were prepared at different pH values from 0 to 5. Crystalline and amorphous samples, prepared at pH 1 having ion exchange capacities of 1.00 meq/g and 0.90 meq/g respectively, were selected for further studies. The materials show high thermal and chemical stability. Distribution coefficients (K_d values) for 22 metal ions have been determined in demineralised water. Structural studies based on IR, XRD, TGA, DTA are discussed. Some quantitative binary separations such as Mg²⁺–Mn²⁺, Cd²⁺–Mn²⁺, Ba²⁺–Mn²⁺ and Ni²⁺–Cu²⁺ were achieved on a-SnSbAs and ion selective electrodes prepared from c-SnSbAs are reported.     

Three-dimensional wire-in-tube hybrids of tin dioxide and nitrogen-doped carbon for lithium ion battery applications

Design and fabrication of tin dioxide/carbon composites with peculiar nanostructures have been proven to be an effective strategy for improving the electrochemical performance of tin dioxide-based anode for lithium-ion batteries, and thus have attracted extensive attention. Herein, we have successfully prepared a uniquely three-dimensional and interweaved wire-in-tube nanostructure of nitrogen-doped carbon nanowires encapsulated into tin dioxide@carbon nanotubes, denoted as NCNW@void@SnO₂@C, via a facile and novel approach for the first time. Interestingly, one-dimension void space located between nitrogen-doped carbon nanowires and innermost wall of tin dioxide@carbon tubes is also formed. The possible formation mechanism of wire-in-tube nanostructure is also discussed and determined by transmission electron microscopy, X-ray diffraction measurement, laser Raman spectroscopy and X-ray photoelectron spectroscopy characterizations. This unique NCNW@void@SnO₂@C fully combines all the advantages of using a three-dimensional architecture, hollow structure, carbon coating, and a mechanically robust carbon nanowires support, thus exhibiting an excellent electrochemical performance as promising anode materials for lithium-ion batteries. A high reversible capacity of 721.3 mAh g⁻¹ can be remained even after 500 cycles at a current density of 200 mA g⁻¹, as well as a capacity of 456.7 mAh g⁻¹ is obtained even at 3000 mA g⁻¹.     

锂离子电池负极材料纳米SnO2制备及电化学性能研究

利用溶胶-凝胶方法制备出纳米二氧化锡,并对所制备的纳米材料进行扫描电镜SEM、透射电镜TEM、粉末X射线衍射(XRD)、循环伏安(CV)以及循环性能测试.电化学性能测试表明所制备出的纳米电极材料具有较高的放电比容量,在电流密度为0.3mA/cm2、电位区间为0.05～1.2V vs.Li /Li时首次可逆放电比容量可达789mAh.g-1.     

A novel composite containing nanosized silicon and tin as anode material for lithium ion batteries

A novel composite consisting of nanosized Sn and Si as well as some lithium containing phases was synthesized by a mechanochemical reaction between SiO/SnO and Li using high energy mechanical milling (HEMM) with graphite as a dispersant, followed by a thermal treatment. The electrochemically active nanoclusters of Si and Sn derived by the mechanochemical reduction were uniformly distributed in the elastic matrix of lithium-containing phases and graphite. The difference in the reactive potential of Sn and Si with lithium was favorable for reducing the mechanical stress of the active hosts. Furthermore, the dispersion of Sn among the elastic matrix may contribute to an improved electrical connection among the Si based hosts and the current collectors. As a result, the composite presented a rechargeable capacity of 574.1 mAh g⁻¹ after 200 cycles. The capacity fading rate was thus calculated to be less than 0.2% per cycle. The cyclability of the composite was much superior to those of the SnO and SiO electrodes.     

电镀锡和可焊性锡合金发展概况

锡及其合金由于优良的耐蚀性和可焊性而广泛应用于电子工业中。总结了电镀锡、锡铅合金和锡铋合金的分类、特点及应用情况。     

Study of carbonization behavior of polyacrylonitrile/tin salt as anode material for lithium‐ion batteries

Using polyacrylonitrile (PAN) as a template, a composite of tin salt/PAN nanofiber is facilely produced by an electrospinning technique. Under high‐temperature heat treatment, the carbonization of PAN and the crystal growth of tin oxide proceed simultaneously to form a composite structure of tin nanoparticles wrapped in carbon nanofibers (tin@CNF). The composite structure of tin@CNF is controllable by the precursor ratio of PAN with tin salt and the carbonization temperature. The sample Sn1Pan1_700, synthesized from the precursor with weight ratio of SnCl₂:PAN = 1:1 and carbonized at 700 °C, delivers the initial capacity of 1329.8 mAh g^?1 and remains at 741.1 mAh g^?1 at the 40th cycle. The proper morphology of tin nanoparticles wrapped in carbon nanofibers plays an important role in specific capacity and cyclic performance, because the proper structure of carbon fiber hinders the aggregation of tin nanoparticles during the lithiation and delithiation processes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016     

锡及其合金镀层的氧化腐蚀与防护

测试了锡及其合金镀层经电接触润滑保护剂涂覆后的耐湿热性、耐高温老化性及可焊性,分析了锡及其合金镀层的腐蚀防护原理.试验结果表明,涂覆电接触润滑剂可提高锡及其合金镀层的耐湿热性、耐高温老化性及可焊性,效果满足国家标准要求.