Ni-Fe-TiO2复合镀层制备工艺研究

采用电沉积方法在低碳钢上制备了Ni–Fe–TiO2复合镀层。研究了镀液中TiO2微粒含量、电流密度、温度、搅拌速率等工艺条件对复合镀层析氢性能的影响。结果表明,在温度为30°C,TiO2加入量为50g/L,电流密度为25mA/cm2,搅拌速率为300r/min时,可获得活性最佳的复合镀层。扫描电镜观察表明,镀层外观均匀,但微观表面粗糙。     

电流密度对电沉积钴-铁-二氧化锆复合镀层性能的影响

在由FeSO₄·7H₂O 30 g/L、Co SO₄·7H₂O 30 g/L、H₃BO₃ 30 g/L和抗坏血酸1 g/L组成的Co–Fe合金镀液中添加10 g/L自制纳米Zr O₂溶胶,电沉积得到Co–Fe–Zr O₂复合镀层。研究了电流密度对Co–Fe–Zr O₂复合镀层微观结构、厚度、显微硬度和耐蚀性的影响。结果表明,随电流密度从5 mA/cm²增大到30 mA/cm²,Co–Fe–ZrO₂复合镀层的晶粒细化,ZrO₂颗粒复合量、厚度和显微硬度均增大,耐蚀性先改善后变差。当电流密度为25 mA/cm²时,Co–Fe–ZrO₂复合镀层的厚度为18.6μm,显微硬度为349 HV,表面平整致密,耐蚀性最佳。     

镍钨合金电沉积的电流效率和镀层显微硬度

通过调节镀液中不同的Ｎｉ／Ｗ比例、温度和沉积电流密度,研究在焦磷酸盐体系中镍钨合金电沉积的电流效率、沉积层和组成和显微硬度。实验结果表明：合金共沉积的电流效率不高。为了尽量提高合金的沉积电流效率,主要途径宜增大镀液中硫酸镍和钨酸钠的浓度;提高合金沉积电流密度,降低镀液中［Ｎｉ］／［Ｗ］比例,则镀层中的钨含量增大;合金沉积层的显微硬度随镀层中的Ｗ含量提高而增大。     

峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响

研究了峰值电流密度对脉冲电沉积Ni-Co-CNTs复合镀层机械性能的影响。结果表明:当峰值电流密度升高时,镀层表面变得粗糙;随着峰值电流密度的增加,镀层中碳的质量分数先增加后下降,当峰值电流密度为80 A/dm~2时,镀层中碳的质量分数达到最大值;镀层的显微硬度和抗拉强度均在峰值电流密度为100 A/dm~2附近时达到其最大值,且高于直流电沉积时所得镀层的显微硬度值和抗拉强度值。说明采用脉冲电沉积工艺可以提高镀层的机械性能。     

脉冲电沉积工艺参数对Ni-W-P合金镀层性能的影响

针对传统镀硬铬沉积速率低、污染环境等问题,采用脉冲电沉积方法在碳钢表面制备Ni-W-P代铬镀层。采用显微硬度计、扫描电子显微镜、X射线衍射仪和电化学工作站研究了脉冲频率、平均电流密度和占空比对镀层性能的影响。结果表明:随着脉冲频率、平均电流密度和占空比的增加,镀层的硬度和耐蚀性均呈现出先增大后减小的变化规律;当脉冲频率为250Hz,平均电流密度为4.0A/dm2,占空比为30%时,镀层为非晶态结构,表面光滑、平整,结构致密,硬度可达5 140MPa,耐蚀性较好。     

平均电流密度对脉冲镀镍钨合金微观形貌和性能的影响

在硫酸镍15g/L,钨酸钠30g/L,柠檬酸35g/L,烷基有机添加剂1.5g/L,pH为7,温度65°C的条件下,研究了平均电流密度对脉冲镀镍钨合金镀层的外观、结合力、显微硬度、沉积速率、镀层中钨含量及表面微观形貌的影响。结果发现,随着平均电流密度的增大,镀层中钨含量增加,镀层硬度先增大而后趋于恒值。过高和过低的平均电流密度都会引起镀层缺陷,最佳的平均电流密度为5～8A/dm2。     

平均电流密度对脉冲镀镍钨合金微观形貌和性能的影响

在硫酸镍15 g/L,钨酸钠30 g/L,柠檬酸35 g/L,烷基有机添加剂1.5 g/L,pH为7,温度65℃的条件下,研究了平均电流密度对脉冲镀镍钨合金镀层的外观、结合力、显微硬度、沉积速率,镀层中钨含量及表面微观形貌的影响.结果发现,随着平均电流密度的增大,镀层中钨含量增加,镀层硬度先增大而后趋于恒值.过高和过低的平均电流密度都会引起镀层缺陷,最佳的平均电流密度为5～8A/dm2.     

镍钨合金电镀工艺的初步研究

研究了镀液组成和电镀条件对镀层中钨含量和电流效率的影响.确定的最佳工艺配方为:Ni2+13.5 g/L,Na2WO4·2H2O50 g/L,配位剂75 g/L,温度60 ℃,电流密度3A/dm2.在此条件下获得了钨含量为40%～45%(质量分数)的镀层,电流效率为38%.镀层经400℃热处理2.5 h后,硬度可达1 100 HV.     

脉冲电沉积镍-铜合金

采用脉冲电沉积技术在304不锈钢表面制备Ni-Cu合金镀层,镀液组成和工艺条件为:NiSO4ꞏ6H2O 200g/L,CuSO4ꞏ5H2O 10 g/L,十二烷基硫酸钠0.2 g/L,柠檬酸钠80 g/L,糖精0.2 g/L,pH 4.0,温度25°C,搅拌速率30 r/min,平均电流密度40~120 mA/cm2,脉冲频率0~100 Hz,占空比20%~90%,时间30 min。研究了平均电流密度、脉冲频率和占空比对Ni-Cu合金镀层的元素组成、表面形貌和显微硬度的影响,得到较优的工艺参数为:平均电流密度40 mA/cm2,脉冲频率50 Hz,占空比60%。该条件下所得Ni-Cu合金镀层由质量分数分别为56.53%和43.47%的Ni和Cu组成,呈“菜花”状形貌,结晶细致、均匀,显微硬度为614.4 HV。     

电沉积处理络合-超滤过程中含镍浓缩液

在络合-超滤处理含镍废水并得到镍离子质量浓度为418 mg/L浓缩液的基础上,考察了电沉积法处理含镍浓缩液过程中电流密度、初始pH、电解时间、温度、极距、搅拌等参数对电流效率和镍回收率的影响。结果表明:当电流密度、电解时间增加时,电流效率随之下降,而镍回收率增大;当pH、极距增大时,电流效率和镍回收率均先增大后减小;温度升高、低速搅拌均可提高电流密度与镍回收率。在电流密度为3.5 m A/cm~2,pH=4,温度为50℃,电解时间为130 min,极距为10 cm并加入低速搅拌的最优操作条件下,电流效率最高可达42%,镍回收率可达52%,并探讨了电沉积机理。     

新型直接碳燃料电池阴极材料及其性能

考察了Ni-CeO2复合阴极对直接碳燃料电池(DCFC)输出性能的影响. 使用不同组成的Ni-CeO2复合阴极对DCFC性能进行了测试. 结果表明,使用Ni-CeO2复合阴极可显著提高DCFC在500和630℃工作时的电流密度、功率密度和燃料转化效率,500℃下DCFC最大电流密度、功率密度分别为328 mA/cm2和72 mW/cm2. 630℃下DCFC最大电流密度、功率密度分别为474 mA/cm2和108 mW/cm2,电流密度50 mA/cm2时燃料转化效率为70%. 用XRD和SEM对Ni-CeO2复合阴极材料进行了表征,并对Ni-CeO2复合阴极可能的作用机制进行了研究.     

工业磷酸中As(Ⅲ)的电化学沉积

运用恒电流法在铜柱电极上研究了工业磷酸中毒性较大的As(Ⅲ)还原为无毒单质砷的电化学行为。实验表明,当电流密度控制在-0.044 mA/cm2以内时可以很好地将As(Ⅲ)转化为单质砷并抑制砷化氢析出。由塔费尔拟合推算得到As(Ⅲ)转化为单质砷的交换电流密度为-6.324×10-7mA/cm2,此过程为不可逆过程。采用表面积为15.8 cm2的铜柱电极,在电流密度为-0.038 mA/cm2,温度为80℃条件下,将磷酸中As(Ⅲ)含量由10.92×10-6降到0.47×10-6,电流效率达7.55%。     

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.     

电流密度对电镀铜-镍合金微观结构和耐蚀性的影响

采用直流电沉积法在高锰铝青铜基体上制得Cu-Ni合金镀层,镀液组成和工艺条件为:CuSO4·5H2O 20 g/L,NiSO4·6H2O 84 g/L,C6H5O7Na3·2H2O 75 g/L,十二烷基硫酸钠0.5 g/L,H3BO320 g/L,电流密度15~30 mA/cm^2,pH 7,温度55℃,搅拌速率300 r/min,时间60 min。研究了电流密度对Cu-Ni合金镀层元素成分、微观形貌和耐蚀性的影响。结果表明,在电流密度30 mA/cm^2下所得到的Cu-Ni合金镀层最厚,为25μm,耐蚀性最好,经乙酸盐雾试验168 h后表面仅有几个微小的腐蚀坑。     

Effect of Electrodeposition Parameters on the Microstructure and Corrosion Behavior of ‎DCPD Coatings on Biodegradable Mg–Ca–Zn Alloy

In this study, DCPD (Brushite, CaHPO₄.2H₂O) coatings were prepared on the surface of a Mg–Ca–Zn alloy using different current density (0.15–1.2 mA/cm²) and deposition time (5–90 min). The results revealed that DCPD with needle‐like morphology was observed for the current density between 0.15 and 0.4 mA/cm²?, whereas ?plate‐like morphology was obtained at current density above 0.8 mA/cm². The results showed that surface roughness increased with increasing current density. The lowest corrosion rate of 0.14 mm/year was obtained for the dense and uniform DCPD coating ?at 0.4 mA/cm², while further increase has deleterious effect on the corrosion resistance.     

模拟体液中电沉积制备磷酸钙盐涂层的研究

采用电沉积方法在模拟体液中制备磷酸钙盐涂层,研究了电流密度、电解液浓度、电沉积时间以及后处理对涂层表面形貌、组分和结构的影响。研究表明：在1～10mA／cm^2电流密度下沉积60～75min可以在模拟体液中制备结晶度较低的磷酸钙盐类涂层,涂层分别经模拟体液、碱液和水热处理后前驱体都转变为羟基磷灰石。     

羟基氧化镍的电解制备，结构表征和电化学性能研究

NiOOH was prepared by one-step electrolysis of spherical Ni（OH）2 and the effects of electrolysis parameters were examined. The highly pure NiOOH was obtained after electrolysis at a current density of 60mA.g^-1 and 30℃ with anodic potential controlled in the range of 1.73-1.85V （vs. Zn/ZnO） for 360min. The NiOOH samriles were characterized bv X-ray oowder diffraction （XRD） and scanning electron microscope （SEM） analysis.Resuits indicate that the electrolysis product is spherical NiOOH doped with graphite. Charge and discharge tests show that the prepared NiOOH offers a discharge capacity of over 270mAh·g^-1 at current density of 30mA·g^-1 and can be directly used as cathode material of alkaline Zn/NiOOH batteries. Galvanostatic charge/discharge and cyclic voltammetry （CV） tests reveal good cycling reversibility, of the NiOOH electrode.     

Tungsten and nickel tungsten carbides as anode electrocatalysts

Tungsten and nickel tungsten carbides were evaluated as the anode catalysts of a polymer electrolyte fuel cell (PEFC). These catalysts were prepared by the temperature-programmed carburization of tungsten and nickel tungsten oxides from 573 to 873-1073 K in a stream of 20% CH₄/H₂ and kept at temperature for 3 h. The 30% tungsten and nickel tungsten carbides mixed with Ketjen carbon (KC) were evaluated by cyclic voltammetry and linear sweep voltammetry using a rotating disk electrode and electrocatalytic activity (I-V performance) using a single cell. The W1023/KC catalyst achieved a power density of 6.4 mW/cm² (current density: 15.2 mA/cm²) which corresponded to 5.7% of that achieved by a commercial 20% Pt/C catalyst in a single cell (20% Pt/C: 111.7 mW/cm²) using our setup. From the XRD data, α-W₂C together with a small amount of WC was active during the anodic oxidation. The maximum power density of the 30 wt% 873 K-carburized NiW/KC was 8.2 mW/cm² at the current density of 19.0 mA/cm² which was 7.3% of the 20 wt% Pt/C.     

镍-纳米二氧化钛复合镀层的制备及性能

以多孔泡沫镍为基体,通过在瓦特镀镍液中复合电沉积,得到Ni-TiO2复合镀层.研究了阴极电流密度、pH、时间、镀液中纳米TiO2质量浓度及分散剂种类对Ni-TiO2复合镀层的TiO2含量、表面形貌及光催化性能的影响.通过正交试验得到最佳工艺条件为:TiO2质量浓度10g/L,pH=4.0,阴极电流密度30 mA/cm2...