电沉积制备Ni-S涂层电极的研究

以泡沫镍为基体电沉积制备了Ni-S涂层电极.通过对电流密度、电沉积温度、电沉积时间和镀液pH值等条件对涂层析氢性能影响的研究,确定了适宜的电沉积工艺条件;电极涂层的XRD、SEM测试结果表明涂层为非晶态结构、表面颗粒大小均匀且具较大表面积;电解过程中出现了Ni3S2由非晶态向晶态的转变,由于Ni3S2具有较强的吸附氢能力,是析氢反应的催化活性中心,电解过程中Ni3S2的出现降低了电极的析氢电位.模拟电解水实验结果表明泡沫镍基Ni-S涂层电极较Raney-Ni电极具有更好的析氢活性.     

电沉积钯钴合金的工艺研究

电沉积钯镍合金存在质量控制困难、热稳定性差及易引起皮肤过敏等问题,而钯钴合金能克服这些不足,且比Pd-Ni合金具有更高的耐磨性、耐蚀性及热稳定性.通过极化曲线研究了钯钴合金的电沉积行为,并讨论了镀液中钴钯离子质量比、温度、pH值以及电流密度等工艺参数对电沉积钯钴合金组成的影响,获得了电沉积钯钴合金的最佳工艺条件为:镀液温度35℃,pH值8.5,电流密度10 A/dm2.结果表明:钴的极化大,极化度也大;电沉积时,钯催化钴沉积,钯钴合金共沉积时呈现与钯相似的阴极行为.合金组成是各工艺参数的函数,钯钴合金镀层中钴的含量随镀液中Co2 /Pd2 质量比的增大而线性增加,随电流密度的增大而显著增大.镀液温度、pH值均对镀层成分有一定的影响.     

碱性锌酸盐体系锌钴合金电镀工艺研究

目前国内对碱性锌酸盐体系电镀锌钴合金的研究较少。研究了碱性锌酸盐Zn-Co合金电镀体系中合金镀液组成及工艺条件对镀层Co含量的影响,得到了最佳镀液组成及工艺条件:锌钴离子总浓度0.3 mol/L,锌钴离子摩尔比9∶1,150 g/L氢氧化钠,15.0 m L/L添加剂A,1.0 m L/L添加剂B,电流密度Jc3 A/dm2,温度25~30℃。在最佳工艺条件下可得到Co含量为2.0%~2.2%的Zn-Co合金镀层。结果表明:Zn-Co金的沉积表现为异常共沉积;在一定范围内,镀层中钴含量的变化会影响镀层光亮度的变化;钴配位剂对Zn-Co合金的共沉积电化学行为不造成影响。     

镍钴合金电沉积中硫酸钴影响的探讨

电沉积镍层硬度低,耐磨性差,在瓦特型镀镍液中加入硫酸钴可以提高镀层的抗热性能、耐蚀性能和韧性.采用硫酸盐电解液电沉积镍钴合金,研究了电解液中硫酸钴浓度与镀液分散能力、深镀能力的关系及其对镀层显微硬度、孔隙率和内应力的影响.同时,利用扫描电子显微镜分析了沉积层的表面形貌.结果表明:随着镀液中硫酸钴浓度的增大,镀液的分散能力下降,深镀能力升高;镀层显微硬度显著提高,内应力和孔隙率也有所增加.镍钴合金沉积层比纯镍镀层更细致、结晶均匀.     

Ti/Pb-WC复合镀电流密度对镀层性能的影响

为了寻找理想的电催化电极及减少制备工序,采用复合电沉积方法在钛基材上制备了Pb-WC镀层.采用SEM、电化学测试等对纯铅层及Pb-WC镀层的表面形貌、元素组成及电化学性能进行了对比研究,分析了电流密度对沉积速率以及镀液中WC浓度对镀层中WC含量的影响.结果表明:电流密度为4 A/dm2,镀液中WC的浓度为30 g/L时...     

工艺条件对化学镀Ni-Co-P合金的影响

采用硼酸为缓冲剂 ,柠檬酸钠为络合剂化学镀Ni Co P合金。考察了镀液pH值、钴离子浓度和温度对化学镀Ni Co P沉积速度的影响 ;研究了钴离子浓度对镀层组成的影响 ,获得了化学镀Ni Co P合金的最佳工艺条件为 :镀液pH值为 7.0 ,操作温度 90℃ ,CoSO4 ·7H2 O浓度为 11g/L。此工艺下镀液稳定性好 ,镀层沉积速度快 ;所得镀层为非晶结构。     

Q235A钢电沉积镍的工艺优化

为了进一步探讨Q235A钢电沉积镍层残余应力、力学性能与镀覆工艺参数的关系,以瓦特镀镍液为基础,采用直流电沉积法,在Q235A钢表面电镀镍。采用X射线衍射仪、纳米力学测试系统、表面轮廓测量仪测试了镍镀层的残余应力、显微硬度、弹性模量及表面粗糙度;探讨了电流密度、温度、p H值对镍镀层力学性能的影响规律,以正交试验法优选了最佳工艺。结果表明:电流密度3.0 A/dm2,温度45℃,p H值3.5时,镍镀层的性能最佳,晶粒粒径为34.8 nm,镀层显微硬度达到3.86 GPa,弹性模量达到238 GPa,表面粗糙度为0.182μm。     

镀钴泡沫镍基板界面机理研究

研究了泡沫镍镀钴镍电极的初期化成行为,发现在电池端电压0.2V附近出现一个充电电压平台,1.0V附近出现第二个充电电压平台,而纯泡沫镍做基板的镍电极无此现象.循环伏安和XRD测试验证了两个电压平台对应的反应是Co氧化为Co(OH)2和Co(OH)2氧化为CoOOH反应.EPMA线扫描显示,镍电极化成后基板表面钴元素呈梯度分布.结果表明,泡沫镍表面的金属钴通过电化学溶解沉淀机理,在基板附近生成梯度分布的CoOOH.     

电镀镍-钴合金对La-Mg-Ni基贮氢合金电化学性能的影响

为了改善La-Mg-Ni基贮氢合金的循环稳定性和综合电化学性能,研究了电镀镍-钴合金对La0.88Mg0.12Ni2.95Mn0.10Co0.55Al0.10贮氢合金粉末表面形貌和电极电化学性能的影响.FESEM表明,电镀处理后合金粉末表面沉积了球状的镍-钴合金颗粒.电化学性能测试表明,贮氢合金电极的放电容量、高倍率放电性能和循环稳定性均得到了显著改善.200周循环时合金电极的容量保持率从未处理合金电极的60%提高到镀覆镍-钴合金的80%,在放电电流密度1080mA/g下的高倍率放电性能提高了23%.线性极化曲线和电化学阻抗分析结果显示,包覆镍-钴合金后贮氢合金电极表面的电荷转移速率加快,电催化活性提高.     

无镍枪色锡-钴合金电镀工艺

为了节约镍资源及降低传统枪色电镀产品的毒性,开发了一种无镍枪色锡-钴合金电镀工艺:采用焦磷酸盐体系并添加光亮剂直接在铜片表面进行锡-钴合金电镀。探讨了镀液组成、温度、pH值及电流密度对镀层外观、镀液稳定性的影响,确定了其最佳工艺参数:250.0 g/L焦磷酸钾,20.0 g/L硫酸亚锡,15.0 g/L硫酸钴,0.6 g/L光亮剂1,2.0 g/L光亮剂2,3 mL/L 25%氨水,温度45℃,pH值8.5,电流密度0.5 A/dm2,施镀时间3 min。该工艺所得镀层颜色呈枪色,均匀致密,附着力好,且镀液稳定。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.