Effects of chloride, bromide and iodide ions on internal stress in films deposited during high speed nickel electroplating from a nickel sulfamate bath

The effects of chloride, bromide and iodide additions on the internal stress developed in nickel films deposited during high speed electroplating from nickel sulfamate baths operated close to the nickel ion limiting current density were investigated. The variations in internal strain in the films were detected in situ using a resistance wire-type strain gauge placed on the reverse side of the copper substrate. The film resistance on the as-plated electrodes was measured using an electronic current interrupter technique. The effects of chloride, bromide, and iodide additions could be classified into two groups: (a) chloride and bromide ions, and (b) iodide ions. For chloride and bromide additions over the concentration range of 0.1 to 0.5M, the nickel deposits exhibited a block- and pyramid-like texture with a (200) crystal orientation. The internal tensile stress developed in 20m thick nickel films deposited in the presence of these two halides was as low as 140–170MPa. Conversely, for additions of iodide, at iodide concentrations greater than 0.1M the deposited nickel exhibited a fine granular texture of disordered crystal orientation. The internal tensile stress developed in 20m thick nickel films deposited from these latter baths tended to rise with increasing iodide concentration to values considerably higher than those observed at similar concentrations of NiCl₂ or NiBr₂.     

镀液中氨基磺酸镍质量浓度对电镀镍层析氢催化活性的影响

采用由10 g/L NiCl₂·6H₂O、30 g/L NH₄Cl和310～390 g/L Ni(NH₂SO₃)2·4H₂O(氨基磺酸镍)组成的镀液(pH=3.8),在温度35°C和电流密度3 A/dm²的条件下电镀30 min,获得镍电极。研究了镀液中氨基磺酸镍质量浓度对镍镀层表面形貌和析氢催化活性的影响。结果表明,镀液中氨基磺酸镍质量浓度为350 g/L时,镍镀层结晶最细致,析氢催化活性和稳定性最佳。     

光亮镀镍液中硼酸和氯化镍的连续滴定

介绍一种光亮镀镍液中硼酸和氯化镍的测定方法。采用732型阳离子交换树脂分离镍及其它阳离子后,分别用氢氧化钠和硼酸银滴定硼酸和氯离子,分析结果表明,本方法简便快速、准确度高。     

Properties and microstructure of nickel electrodeposited from a sulfamate bath containing ammonium ions

A 70 m thick Ni layer was electrodeposited from a sulfamate bath containing various amounts of ammonium ions onto a copper plate. The detailed microstructure of the Ni deposits was characterized using a plane-view and cross-sectional transmission electron microscopy (TEM). The textures of the Ni deposits were also determined using conventional X-ray diffraction. Experimental results indicated that ammonium ions suppressed the lateral growth of Ni deposits and favoured out growth, thus leading to the growth of [1 1 0] and [3 1 0] oriented deposits. A structural refinement effect was observed after ammonium ions were added to the sulfamate bath. Ammonium ions also increased the internal stress and hardness of the deposits. A general Hall–Petch relationship was observed for the dependence of deposit hardness on the average grain size of the Ni deposits. The adsorption of atomic hydrogen and the polar NH₃ molecule explains the effect of ammonium ions on the electrocrystallization of Ni.     

硫酸盐电铸镍内应力的影响因素

研究了NiSO4·6H2O质量浓度、NiCl2·6H2O质量浓度、温度和阴极电流密度等工艺参数对硫酸盐电铸镍层内应力的影响。通过铜箔阴极弯曲法半定量地测定了镍铸层的内应力,采用扫描电镜和X射线衍射表征了镀层在不同应力状态下的表面形貌和微观结构。结果表明,当NiSO4·6H2O质量浓度为100～150g/L时,其变化对内应力影响较大;镀液中氯离子浓度的增加会增大镀层内应力;低温和大电流密度条件下获得的镀层具有大的拉应力,高温小电流则有利于降低镀层的拉应力。     

镀镍清洗水中镍、硼酸的回收再利用

通过延长滴液时间减少了硫酸镍、氯化镍和硼酸等的带出损失,优化了摩托车消声器电镀生产工艺,实现了清洗水中镍盐和硼酸的回收使用,降低了生产成本,减少了环境污染.     

Electroplating of a Co–Cu alloy from a citrate bath containing boric acid

The effects of bath composition, current density and temperature on cathodic polarization, cathodic current efficiency of codeposition, composition and structure of Co–Cu alloys electroplated on a steel substrate from citrate baths have been studied. Addition of boric acid to citrate electrolyte increases the percentage of Co in the deposits and improves the quality of these deposits. The cathodic current efficiency of the baths is relatively high and increases with increases in the metal content in the bath and the current density but decreases with temperature. The composition of the deposit is controlled by the applied current density. At low current densities, Cu‐rich alloys were obtained. At higher current densities, the composition of the alloys was controlled by the limiting current density of Cu codeposition. The Co content of the deposits increases with increases in the metal content in the bath and the temperature. The structure of the deposited alloys was characterized by anodic stripping and X‐ray diffraction techniques. The deposited alloys consisted of a single solid solution phase with a face‐centred cubic structure. © 2000 Society of Chemical Industry     

硼酸凝固浴对MF-PVA纤维结构与性能的影响

以三聚氰胺(M)、甲醛(F)、聚乙烯醇(PVA)水溶液为原料反应制得纺丝原液,经湿法纺丝得到三聚氰胺甲醛-聚乙烯醇(MF-PVA)纤维。研究了在凝固浴中加入硼酸对MF-PVA纤维结构及性能的影响。采用凯氏定氮法、扫描电子显微镜、单纤电子强力仪和极限氧指数(LOI)仪表征了纺丝过程氮流失率、纤维形貌结构、力学性能以及阻燃性能。结果表明:在凝固浴中加入硼酸可以有效地控制MF树脂的溶出,随着硼酸添加量的增加,纤维的氮流失率明显降低,断裂强度增加,断裂伸长率减小,LOI提高。当添加硼酸的质量分数为7%时,纤维的氮流失率只有14.64%,其LOI达到40%,但纤维表面变得粗糙。     

含铵盐的硫酸盐三价铬镀铬液中硼酸的测定

制定了测定含铵盐的硫酸盐三价铬镀铬液中硼酸的方法。用柠檬酸钠掩蔽三价铬离子和镍杂质,用甘露醇与硼酸反应生成较强的配合酸。以变色pH范围为6.8～8.4的酚红作为指示剂,用氢氧化钠标准溶液滴定配合酸,避免了硫酸铵对测定硼酸的影响。测定结果的相对平均偏差为0.28%,回收率为99.34%～100.46%。     

氨基磺酸镍电铸层产生针孔、麻点的原因分析及工艺改进

通过对比试验对润湿剂、金属离子杂质、有机物杂质、槽液pH以及固体颗粒物等因素进行排查,得出氨基磺酸盐电铸镍层产生针孔、麻点的原因,并提出相应的工艺改进措施。槽液中存在固体颗粒和槽液pH不在工艺范围内是造成镀层表面针孔和麻点的主要原因。为保证产品质量,电铸时应采用精密循环过滤系统对电铸槽液进行连续净化并控制槽液pH在允许的工艺范围内。     

析氢对电沉积镍枝晶生长的影响

采用点电极电沉积的方法,在环形电解池中用自行设计的试验装置研究了不同电压和NiSO4质量浓度时,析氢对电沉积金属镍枝晶二维生长行为的影响。研究发现,析氢对沉积产物的形貌影响显著,氢气的大量析出有利于枝晶产生分枝,使沉积物的形貌趋于致密。     

电沉积制备镍-铁-钨合金析氢电极的工艺研究

以紫铜片为基体电沉积制备了Ni–Fe–W合金电极。研究了镀液中不同组分的浓度和工艺条件对Ni–Fe–W合金析氢性能的影响,得到最佳镀液配方和工艺条件为:NiSO4·6H2O80g/L,FeSO4·7H2O20g/L,Na2WO4·2H2O0.020mol/L,Na3C6H5O7·2H2O 0.5 mol/L,H3BO3 0.65 mol/L,Na2SO4 0.1 mol/L,十二烷基硫酸钠0.1 g/L,pH 5~6,温度30°C,电流密度4 A/dm2,磁力搅拌800 r/min,时间30 min。在该条件下所得Ni–Fe–W合金电极表面Ni、Fe和W的原子分数为63.79%、34.35%和1.86%,具有较大的比表面积,在30%KOH溶液中的析氢催化活性较好。     

Effect of boric acid on thermal dehydrogenation of ammonia borane: H2 yield and process characteristics

We have recently demonstrated that boric acid (H₃BO₃, BA) is a promising additive to decrease onset temperature as well as to enhance hydrogen release kinetics for thermolysis of ammonia borane (NH₃BH₃, AB). The observations suggest that tetrahydroxyborate ion released by heating BA serves as Lewis acid and catalyzes AB dehydrogenation. Using this approach, we obtained high H₂ yield at 85°C, along with rapid kinetics. Various operating conditions were investigated, such as reactor temperature, AB wt %, and particle size of BA. Even in the presence of 10 wt % BA, high H₂ yield (13 wt %) and trace amount of ammonia (10–20 ppm) were obtained at 80°C, proton exchange membrane (PEM) fuel cell operating temperature. To our knowledge, such H₂ yield value is higher than from any other method using AB with additive or catalyst at PEM fuel cell operating temperatures. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3359–3364, 2013     

西藏硼镁矿制取硼酸联产碳酸镁工艺研究

提出了西藏硼镁矿综合利用的新工艺,即用硫酸铵复分解法分解西藏硼镁矿制取硼酸和碳酸镁。考察了反应温度、反应时间、硫酸铵的初始浓度、硫酸铵的用量比等工艺条件对硼浸出率的影响。较佳工艺条件为：反应温度100 ℃、反应时间2~2.5 h、硫酸铵的初始浓度为9%~11%（质量分数）、硫酸铵的用量为理论量的110%。在此工艺条件下,硼酸的收率可达95%,碳酸镁的收率可达90%以上。该工艺充分利用了西藏硼镁矿的硼、镁资源,提高了硼的收率。     

硼酸喷雾包覆改性镍钴铝酸锂的制备及其电化学性能研究

针对镍钴铝酸锂（NCA）三元正极材料普遍存在的循环寿命差、浆料容易凝胶等缺点进行了硼酸喷雾包覆的改性。采用X 射线衍射仪（XRD）、扫描电镜（SEM）、透射电镜（TEM）及电化学测试等方法对硼酸包覆改性前后的材料性能进行了对比表征和分析。结果表明：喷雾包覆后可以在NCA正极材料表面形成一层保护层,改性后的NCA三元正极材料循环寿命有明显提升,特别是高温（45 ℃）1C/1C倍率下循环50次容量保持率由改性前的88.0%提升至改性后的95.2%,提升近7%;硼酸包覆可以改善NCA表面特性,使正极浆料稳定性大大提高。改性后的NCA正极浆料可以稳定放置168 h（7 d）,解决了NCA正极材料容易凝胶的问题。     

大柴旦柱硼镁石矿酸法制硼酸工艺优化研究

针对大柴旦柱硼镁石矿特点．对酸法制硼酸进行了工艺优化研究。通过试验,缩短了酸化反应时间,提高了反应收率,达到了优化工艺的目的。该工艺已在实际生产中应用。     

镀镍液中铁杂质的影响及处理方法

分析了镀镍液中铁杂质的产生途径及其对镀镍层质量的影响。介绍了不同情况下铁杂质的处理方法:ρ(Fe2 )<200mg/L时,可采用添加WZ-Fe除铁剂的方法处理;日常维护,可以采用小电流电解方法除去铁杂质;当Fe2 的质量浓度很高时,用KMnO4或H2O2氧化法进行处理。     

从硼镁矿硫酸分解液中分级结晶硼酸和水镁矾

目前在中国用硫酸分解硼镁矿直接制取硼酸（一步法）的B2O3收率不高。对硼酸母液的利用方法主要有将硼酸母液蒸浓后冷却制硼镁肥；蒸浓冷却至室温再用浮选法或重选法进行分离；加入MgCl2做盐析剂等方案，但都存在一定的问题。经分析25，100℃H3BO3-MgSO4-H2O体系相图，确定了从硼镁矿的硫酸分解液中分级结晶硼酸和水镁矾的生产工艺，并指出可以采用冷却式Oslo结晶器结晶硼酸以获得大粒晶体；用蒸发式Oslo结晶器结晶可以获得大粒水镁矾晶体，并可确保水镁矾离心机安全运转.     

Effects of butyric acid stress on anaerobic sludge for hydrogen production from kitchen wastes

BACKGROUND: Anaerobic digestion is an alternative technology to achieve the dual benefits of hydrogen production and waste stabilization from kitchen wastes. In this work, the butyric acid stress on anaerobic sludge was investigated in order to improve the tolerance of sludge against organic acids, and to enhance hydrogen accumulation. RESULTS: The tolerance of butyric acid in anaerobic sludge increased with the stress concentration, however, it decreased at concentrations greater than of 4.0 g L^?1. The maximum hydrogen yield reached 63.72 mL g^?1 VS at 4.0 g L^?1 stress, representing an increase of 114% compared with the control group. The concentration of volatile solids (VS) of the sludge and SCOD increased steadily with time up to 20 h. At 4.0 g L^?1 butyric acid stress, the maximum activity of β‐glucosidase, BAA‐hydrolysing protease and dehydrogenase enzyme were 14912.1 µmol PNP g^?1 TS h^?1, 134.14 µmol NH₄‐N g^?1 TS h^?1 and 7316.42 µg TF g^?1 TS h^?1, which were 2.78, 1.90 and 2.01 times that of the control, respectively. CONCLUSIONS: The feasibility of butyric acid stress on anaerobic sludge to increase hydrogen production from kitchen wastes was demonstrated. Remarkably, 4.0 g L^?1 butyric acid stress was found to be favorable for improving the tolerance of butyric acid in sludge as well as hydrogen yield in the experiment. Copyright © 2010 Society of Chemical Industry     

Effect of hydrogen on carbon deposition from carbon monoxide on nickel catalyst

The role of hydrogen in carbon deposition on Ni has been studied at H₂/CO < 1 and 698 K by determining the respective rates of the carbon-forming reactions: (1) CO + H₂ -C + H₂O and (2) 2CO C + CO₂. The steady-state rate of reaction (1) increases in proportion to H₂ pressure. On the other hand, reaction (2) is facilitated by the addition of an extremely small amount of H₂, so that the rate becomes about eight times that for pure CO but hardly varies as more H₂ is added. Similarly, there is a great difference in catalytic activity for ethylene hydrogenation between spent catalysts obtained in the deposition with and without H₂. These findings suggest that hydrogen, even in a small amount, makes free Ni surface area larger than for pure CO.