配位剂对弱酸性体系电沉积Sn-Ag-Cu镀层的影响

在含有甲磺酸盐和碘化物的弱酸性镀液中电沉积得到了Sn-Ag-Cu三元合金镀层.研究了该镀液体系中配位剂的用量对Sn-Ag-Cu合金镀层外观和镀液电流效率的影响,探讨了配位剂对镀液阴极极化的影响.结果表明,配位剂K4P2O7、KI、TEA的加入使Sn、Ag、Cu三种金属的沉积电势趋于一致,能够实现共沉积.优化的镀液组成及工艺条件为:0.2 mol/L Sn(CH3SO3)2,4.5 mmol/L AgI,1.5 mmol/L Cu(CH3SO3)2,0.6 mol/L K4P2O7,1.35mol/L,0.225mol/L TEA,1 g/L光亮剂,1 g/L抗氧化剂,温度20℃,pH 5.5.     

Study of the electrochemical deposition of Sn-Ag-Cu alloy by cyclic voltammetry and chronoamperometry

The electrochemical deposition of Sn-Ag-Cu alloy from weakly acidic baths onto glassy carbon electrodes (GCE) was studied by cyclic voltammetry (CV) and chronoamperometry (CA). The properties of the electrodeposits were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometery (EDS) and X-ray diffraction (XRD). Test results indicate that the two cathodic peaks in the CV curves, at −0.6 V and −0.85 V during the forward scan towards the negative potentials, correspond to the irreversible deposition of a solid solution of tin, silver and copper. The underpotential deposition (UPD) of Sn occurs at −0.6 V during the cathodic period and the amount of Ag and Cu in the Sn-Ag-Cu alloy decreases with increasingly negative cathodic potentials. During the forward scan, towards the positive potentials used in CV testing, cathodic peaks at −0.85 V appear in the CV curves for baths containing mixtures of tin salts and triethanolamine (TEA). This corresponds to a reduction of transient complex ions [Sn(TEA)_x]²⁺ on the surface of the cathode. Furthermore, the formation and reduction of [Sn(TEA)_x]²⁺ is a diffusion controlled process. On the surface of the GCE, the actual nucleus growth mechanism of the Sn-Ag-Cu alloy is represented by the progressive nucleation model.     

Effect of polarization type on properties of Ni–W nanocrystalline electrodeposits

Nickel–tungsten nanocrystalline coatings were electrodeposited from a Watts type bath onto a copper substrate, at different current densities selected from activation, mixed and diffusion controlled regions in the cathodic scan plot at room temperature. The results confirm that tungsten codeposition proceeds via the adsorption and reduction of complexes produced in the bulk of solution. The coatings obtained were single phase solid solutions and their grain sizes increased with current density. A cauliflower-type surface morphology with highest hardness was obtained when the current density was in the activation controlled region. The surface morphology obtained in the mixed controlled region was distorted, and then converted to a nodular morphology in the diffusion controlled region. In the mixed control region, coatings with the highest corrosion resistance were obtained due to the lowest exchange current density for water reduction.     

Effect of diethanolamine and triethanolamine on the properties of electroplated Zn–Ni alloy coatings from acid bath

In the present work, zinc–nickel alloy coatings have been produced under direct current conditions from an acid bath with different concentrations of diethanolamine (DEA) and triethanolamine (TEA). The produced coatings were analysed through chronopotentiometry, microhardness, X‐ray diffraction and MEB techniques. The compositional analysis of the films showed that the Zn–Ni electrodeposition is anomalous for all the systems. Ethanolamines augmented the anomalous behaviour. The hindering in the Ni (II) reduction will be more effective due to complexation of Ni (II) catalyst with ethanolamines. Electrochemical and structure analysis of deposits indicated the presence of γ and highly Zn‐enriched phases. The presence of these additives resulted also in coatings with finer grains. The behaviour of modified Zn–Ni alloy coatings in corrosion solution of 3% NaCl was investigated through potentiodynamic polarisation and electrochemical impedance spectroscopy. It was found that the obtained Zn–Ni/3 mM TEA alloy exhibited better corrosion resistance compared to pure Zn–Ni alloy electrodeposited at similar conditions. © 2012 Canadian Society for Chemical Engineering     

低温阴极电泳漆的制备及性能

随着人们对环境保护以及低能量消耗要求的不断提高,低温固化阴极电泳漆已经成为电泳漆的发展趋势之一。合成了封闭物异氰酸酯固化交联剂,并探讨了反应时间和反应温度对封闭率的影响,最后以氨化改性环氧树脂为基料树脂合成了低温固化阴极电泳漆。实验结果表明：在150℃／20min的固化条件下,漆膜能得到完全固化,经过漆膜综合性能实验,在选择合适的电泳工艺参数下,可以得到硬度较高、耐潮、耐盐、耐酸碱性能好的漆膜。     

温度对N-月桂酰肌氨酸三乙醇胺反应物结构及性能的影响

N-月桂酰肌氨酸三乙醇胺反应物是性能优异的表面活性剂，具有良好的生物降解性，广泛地应用于日化、金属加工及液压传动介质等行业。重点研究了反应温度、时间对N-月桂酰肌氨酸三乙醇胺反应物结构的影响，通过红外光谱及核磁共振对其结构进行了分析确认。结果表明：低温（75℃）条件下，更容易获得阴离子型表面活性剂（产物A），高温（130℃）条件下，更容易获得非离子型表面活性剂（产物B）。同时，对两种产物的泡沫性能及抗硬水性进行了对比研究发现，当质量浓度小于0.8%时，产物A的表面张力小于产物B的表面张力，且在质量浓度为0.3%时，表面张力均达到最小，此时产物A与产物B的泡沫半衰期分别为22.56min和28.26min。当质量浓度为1.0%时，产物B与产物A相比，其抗硬水能力提升了23.57%，更有利于乳液稳定。通过研究以期为N-月桂酰肌氨酸三乙醇胺的理论研究及实际应用提供参考。     

Effect of the electrode-bulk interface on the dielectric properties of BBZT ceramics

The effects of the electrode-bulk interface on the dielectric properties of Ba_0.9988Bi_0.0008Zr_0.2Ti_0.8O₃ (BBZT) ceramics with a slight change in the thickness (≤15%) were investigated. In BBZT ceramics, the dielectric constant decreases with the increase of thickness, and the interface between electrode and bulk ceramics is considered the main reason. A formula is proposed to calculate the dielectric constant of bulk materials. According to the formula, the electrode-bulk interface has a slight influence on the frequency characteristics of the dielectric constant. However, the ferroelectric to paraelectric phase transition temperature changes from 10 °C to 15 °C for bulk ceramics when the electrode-bulk interface is taken into consideration. In a range of 0 °C–75 °C, obvious differences between ε_B and ε_T are observed due to the electric field induced by removable carriers. The dielectric tunability is degraded by the influence of electrode-bulk interface. BBZT ceramics have considerable tunability (>65% @100 kHz) and a low loss tangent (<0.006 @100 kHz) with an excellent FOM value (>270). This study demonstrates a method of calculating the dielectric constants of bulk ceramic layers and provides a theoretical basis for improving the performance of bulk materials using interfacial layers.     

Effect of dysprosium doping on structural and vibrational properties of lead-free (Na0.7K0.3)0.5Bi0.5TiO3 ferroelectric ceramics

This study describes the effect of Dy³⁺ doping of lead-free ferroelectric sodium potassium bismuth titanate ((Na_0.7K_0.3)_0.5Bi_0.5TiO₃; NKBT) ceramics on their structural, optical, and vibrational properties. X-ray diffraction and Rietveld refinement analyses revealed that NKBT samples exhibited a rhombohedral perovskite structure belonging to the R3c space group, with the incorporation of Dy³⁺ resulting in structural parameter change and local atomic structure shift to tetragonal P4mm, as supported by the appearance of new Raman modes. Increased Dy³⁺ content decreased the NKBT band gap from 3.4 to 3.3 eV, which was ascribed to the introduction of Dy 4f levels between valence and conduction bands. Ferroelectric behavior studies combined with transport measurements explained the unexpected ferroelectric response weakening of Dy³⁺-modified NKBT by increased leakage current densities.     

Studies on preparation and ion-exchange properties of weakly acidic cation exchange fiber by preirradiation-induced graft copolymerization with electron beam

Weak acidic cational exchange fibers were obtained by means of preirradiation-induced graft copolymerization of methacrylic acid, acrylic acid, and diglycol acrylate onto polypropylene nonwoven fabric with electron beam. Effects that influence grafting and the exchange adsorptive property of the ion-exchange fibers obtained toward transition and rare-earth metal ions have been investigated. © 1994 John Wiley & Sons, Inc.     

Effect of the structure and properties of hearth carbon blocks on premature shutdown of electrolytic baths

Premature shutdown of electrolytic baths after a short service life leads to an increase in the cost of aluminum and serious economic losses. The most important element governing the service life of an electrolytic bath is the hearth that is lined with refractory hearth blocks. Presence of one concealed crack, that is exposed in the start-up period, may lead to failure of the whole electrolyzer in the first year of service. There are many producers and users of hearth blocks, and there are many specifications for cathode hearth blocks, although the requirements for them are selected in a very empirical way without considering actual service conditions. Scientifically based requirements for the material of hearth blocks is still in the formation stage. In 2004 in four aluminum enterprises under major repair hearth blocks were used from nine different producers that made it possible during evaluation of the statistics for shutting down young baths to determine the effect of the structure and properties of hearth blocks on the service life of electrolyzers and to formulate requirements for hearth block material. The contribution of permeable porous cathode carbon blocks on premature shutdown of electrolyzers by a mechanism of hearth uplift due to formation of a lens of electrolyte and refractory reaction products is demonstrated. Critical gas permeability and the maximum size of permeable pores in refractory hearth units are determined. Applicability of the first and second Hasselman criteria for the heat resistance of hearth block materials is demonstrated for predicting shutdown of young baths by a crack development mechanism in blocks due to thermomechanical stresses. __________ Translated from Novye Ogneupory, No. 4, pp. 3–12, April 2008.     

合成条件及添加三乙醇胺对水热法合成TS-1分子筛及其性能的影响

以正硅酸乙酯(TEOS)、钛酸丁酯(TBOT)、四丙基氢氧化铵(TPAOH)分别作硅源、钛源及模板剂水热合成了TS-1分子筛.考察了TEOS水解时的水硅比、TEOS水解温度、TPAOH用量及添加三乙醇胺(TEA)对TS-1分子筛合成及其性能的影响.采用XRD、SEM、N2吸附等手段对试样进行表征,同时以环己酮氨肟化反应考察试样的催化活性.结果表明,TEOS水解过程中,n(H2O)/n(S iO2)在20~40的范围内对TS-1的合成及性能影响不大.水解温度较高(60℃)时,加入少量TPAOH(n(TPAOH)/n(S iO2)=0.125)即可得到性能较好的TS-1,而在水解过程中添加适量TEA则能进一步改善TS-1分子筛的性能.在水解温度为60℃、n(S iO2)∶n(TPAOH)∶n(TEA)∶n(H2O)为1∶0.125∶0.065∶20时合成出的TS-1用于环己酮氨肟化反应,环己酮转化率达到90.7%,环己酮肟选择性达到92.4%,催化活性与高TPAOH用量合成的TS-1接近,而TPAOH的用量大大降低.     

酸性液电镀Zn-Ni合金的操作条件对镀层中Ni含量的影响

研究了酸性电镀光亮Zn-Ni合金中ρ(Ni2 )/ρ(Zn2 )的比值、阴极电流密度、镀液温度、pH对镀层中镍的质量分数的影响。通过扫描电子显微镜(SEM)研究了镍镀层的微观形貌。结果表明,镀层含镍量随着电流密度的增大、温度升高而增大;随着镀液中pH的升高、含镍量的增大而下降。获得了最佳工艺参数:27～100g/LNiSO4.6H2O,25g/LZnCl2,100g/LNaCl,50g/LNH4Cl,25～30g/LNa3C6H5O7.2H2O,10g/LH3BO3,5mL/LL-5A添加剂,30～40mL/LL-5B添加剂,Jk=1.25～6A/dm2,θ=20～40°C,pH=4.5～6.0。     

成核剂1,3-2,4-二（3,4-二甲基）亚苄基木糖醇的合成及其对聚丙烯的改性

以3,4-二甲基苯甲醛和木糖醇为原料合成1,3-2,4-二（3,4-二甲基)亚苄基木糖醇（DMDBX）,将DMDBX作为成核剂使用溶液沉淀法制备DMDBX质量分数分别为0、0.1%、0.3%、0.5%、0.7%、0.9%的聚丙烯（PP）样品,采用红外光谱仪、差示扫描量热仪、X射线衍射仪和偏光显微镜等方法,研究了DMDBX对PP结晶结构和结晶性能的影响。结果表明,DMDBX是PP的有效α晶型诱导剂,DMDBX的加入能诱导大量球晶生成,导致结晶峰尖锐,结晶温度区间变窄,结晶度提高15％左右,FT-IR、X射线衍射和DSC等分析结果一致。在PP中添加0.3%～0.5％DMDBX时,聚丙烯的改性效果最好,结晶度达到最大值。采用修正Avrami方程Jeziorny法处理非等温结晶动力学结果表明,添加DMDBX的PP Avrami指数约为3,说明DMDBX起到了异相成核的作用,使PP结晶过程的成核和生长方式发生了改变。     

配方与工艺因素对EPDM模压发泡材料性能的影响

研究了发泡剂Ｈ在ＥＰＤＭ模压发泡材料中的发泡特性、硫化特性以及两之间的匹配关系对发泡效果的影响,同时还考察了配方和工艺因素对发泡体性能的影响。结果表明,为了获得较高的发泡率和良好的发泡质量,应选择硫化诱导期与发泡剂完全分解时间相当的硫化体系;一次硫化的硫化程度决定着胶料出模时的膨胀;二次硫化的发泡材料收缩率较小;高填充时粒径较大的填料对发泡效果的影响较小。     

三乙醇胺-水介质水热合成二氧化钛及性能研究

以有机溶剂三乙醇胺为矿化剂,T(iOH)4为前驱体水热合成锐钛矿TiO2,研究了水热温度、水热时间、矿化剂的浓度及反应釜填充度对产品光催化性能的影响。结果表明,矿化剂浓度为0.5mol.L-1,反应釜填充度为80%,170℃、水热9h合成的TiO2的光降解甲基橙效果最佳。     

成核剂对聚丙烯结晶形态及力学性能的影响

研究了有机磷酸盐成核剂对聚丙烯(PP)结晶行为及力学性能的影响．采用差示扫描量热法和偏光显微镜分析比较了3种成核剂。结果表明：添加质量分数为0.2％的成核剂,可使PP的结晶峰温度提高15．6～17．8℃。结晶度增加2．5％～10．5％,同时提高了结晶速率,球晶尺寸大幅度降低;试样的拉伸强度、弯曲模量均有提高。弯曲模量提高15．5％～44．9％。     

偶联剂对白炭黑／SBR复合材料力学性能的影响

研究了4种偶联剂KH-550、KH-792、WD-60和HG-305对白炭黑／SBR复合材料力学性能和热空气老化性能的影响。研究结果表明：当KH-550用量为4．0份时,复合材料的综合力学性能最好,与未改的白炭黑／SBR复合材料相比,其拉伸强度和撕裂强度分别提高了77％和24％;复合材料的老化实验结果表明,经偶联剂改性的复合材料的耐热老化性能有所下降,其中HG-305改性的复合材料抗老化性较好。     

基质组成对中间包干式振动料性能的影响

采用中档烧结镁砂(MS95,3~1mm和≤1mm)作骨料,电熔镁砂(MD97,≤0.088mm)为主要基质料,将骨料与基质料的质量比控制在65/35,研制了连铸中间包工作衬用镁质干式振动料。通过常温性能检测和静态坩埚抗渣试验,分别研究了在基质中加入低温结合剂(固体酚醛树脂)、中温烧结剂(分别采用硼砂、氟化钠和六偏磷酸钠)以及抗渗剂(特级矾土和预合成尖晶石)对干式料强度或抗渣渗透性的影响。研究结果表明固体树脂的加入量(质量分数,下同)在3%~5%之间时,干式料的常温强度最佳;中温烧结剂硼砂、氟化钠、六偏的加入量分别在1.5%、1%、1%左右时,对干式料中温烘烤时的促烧结作用最显著,且其促烧作用由强到弱依次是硼砂、氟化钠、六偏;在基质中引入9%特级矾土的基础上再引入2%的尖晶石后,干式料的抗渣渗透性能最佳。     

超声波碱处理改性对丝光沸石结构、酸性质及其催化性能的影响

基于丝光沸石（MOR）催化合成乙酸甲酯稳定性较差及传统碱处理MOR较难引入多级孔的特性,提出了利用超声波对MOR进行碱处理脱硅改性以制备多级孔MOR的技术。采用XRD、SEM、TEM、吡啶红外和N₂吸-脱附等手段对催化剂进行了表征,分别考察了超声波在不同碱浓度处理改性条件下对分子筛催化剂骨架结构、酸性质、孔结构以及催化合成乙酸甲酯性能的影响。结果表明,通过超声波及合适浓度的NaOH碱溶液处理后,MOR分子筛的酸量、介孔孔容、比表面积都增加、孔径分布变宽,催化剂的活性和稳定性等催化性能得以改善。改性后的MOR催化剂二甲醚（DME）转化率由35.3%增加到44.8%,使用寿命大大延长,但碱液浓度过高会严重破坏MOR分子筛骨架结构,催化活性及稳定性快速下降。