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.     

Effects of boric acid on hydrogen evolution and internal stress in films deposited from a nickel sulfamate bath

The effects of boric acid additions on the pH close to the electrode surface, on the hydrogen evolution reaction and on the internal stress in the plated films were studied for the high speed electroplating of nickel from a nickel sulfamate bath at a current density close to the nickel ion limiting current density. The study was carried out at 50 °C and pH 4.0 using a 1.55 M nickel sulfamate plating bath containing boric acid at concentrations ranging from 0 to 0.81 mol L^–1. The variation of the internal strain in the plated nickel films was determined in situ using a resistance wire-type strain gauge fitted to the reverse side of the copper electrode substrate. The solution pH at a distance of 0.1 mm from the depositing nickel film was measured in situ using a miniature pH sensor assembly consisting of a thin wire-type antimony electrode and a Ag/AgCl/sat. KCl electrode housed in a thin Luggin capillary. The addition of boric acid was shown to effectively suppress the hydrogen evolution reaction at nickel electrodeposition rates (18.0 A dm^–2) close to the limiting current density (~20 A dm^–2). Consequently, the solution pH adjacent to the plating metal surface was maintained at a value close to that in the bulk solution and the development of high internal stresses in the deposited nickel films was avoided.     

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。     

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。     

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     

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。     

Electrodeionisation 3: The removal of nickel ions from dilute solutions

The removal of nickel ions from dilute solutions using a process that combines an ion-exchange bed with electrodialysis has been studied. The main aspects include: the concentration of nickel ions in the diluate, the voltage over the cell and the current density distribution along the ion-exchange bed. The current density distribution provides insight into the state of the bed as it is simultaneously loaded with Ni²⁺ and regenerated with an electric potential difference applied perpendicular to it. A simple model is used to describe the state of the bed and the quantity of nickel removed from it as a function of time. Under specific conditions the precipitation of metal hydroxides is observed in the compartment containing the ion-exchange bed. The results show that hydroxide precipitation is related to the nickel concentration in solution and the electric potential gradient across the bed.     

Transport and separation of cobalt,nickel and copper ions with alamine liquid membranes

The transfer and separation of Co(II), Ni(II) and Cu(II) ions across a flat-sheet supported liquid membrane containing Alamine 336 as the mobile carrier dissolved in kerosene solvent has been investigated. Both the Alamine composition in the organic solution and the hydrochloric acid concentration in the feed solution have a marked effect on Co(II) and Cu(II) transport. A maximum flow of these ions at 50% of Alamine in the diluent was obtained. Ni(II) ion was not transported in the whole range of experimental conditions studied and good separation from Co(II) and Cu(II) could thus be performed. With decreasing hydrochloric acid concentration in the feed solution the separation factor of Cu(II) from Co(II) increases thus decreasing the Cu(II) recuperation factor.     

QHS-3型钠钙浮选剂用催化剂生产过程中含铜、镍离子废水的处理

对QHS-3型钠钙浮选剂用催化剂生产过程中产生的含铜、镍离子废水采用常规中和沉淀法与加入金属螯合剂M相结合的方法进行了去除铜、镍离子的研究,结果表明:在最佳工艺条件下,即在溶液的pH值为9.2,聚丙烯酰胺(PAM)加入量为6 mg/L,金属螯合剂M投加量为80～90 mg/L时,处理后的废水中的铜、镍离子的质量浓度达到了国家排放标准.     

Amperometric determination of ammonium ions with a microbial sensor

A sensor for NH⁺₄ ions has been developed, which consists of immobilized micro-organisms (Bacillus subtilis, Pseudomonas aeruginosa, Trichosporon cutaneum) in combination with an electrochemical transducer. This sensor is based on the measurement of acceleration of respiration after addition of NH⁺₄ in the presence of glucose. The physiological background of this signal and its connection with NH⁺₄ ion uptake and/or metabolism is discussed. The response time of the sensor is about 5.10 s for NH⁺₄ ions. A linearity was observed between 0.005 and 0.15 mmol dm^?3 NH⁺₄ ions. The sensitivity of the sensor remained almost constant for 12 days. The sensor was used to determine NH⁺₄ ions in a microbial fermentation broth.     

硫酸盐-柠檬酸盐体系锌锰合金电镀液稳定性的研究

锌锰合金镀液存在电流效率低,镀液稳定性差等缺点,选择硫酸盐－柠檬酸盐体系锌锰合金镀液,研究了阳极,二价锰离子以及连续作用等因素对镀液稳定性的影响,结果表明：采用不锈钢阳极和阴离子膜可提高镀液稳定性,防止二价被氧化,加入氢氧化可消除因补充锌锰离子而积累的硫酸根离子。     

Corrosion resistance of compositionally modulated multilayered Zn–Ni alloys deposited from a single bath

By consecutive deposition at two different current densities from a single sulfate–chloride bath, compositionally modulated multilayered (CMM) coatings of Zn–Ni alloys, with different number, thickness and sequence of the sublayers were obtained. The corrosion resistance of the coatings was studied by potentiodynamic dissolution and by corrosion potential measurement. In the current–potential (stripping) curves two well-defined peaks were observed. With increase in the number of sublayers, regardless of their individual thickness, the correlation between the amount of Zn, dissolved at more negative potentials and the whole amount of the metal in the CMM coatings, decreases. The corrosion potentials of CMM coatings are most positive (–0.940 V vs SSE) when they end with a Zn–Ni18% oversublayer. As a result of the alternation of Zn–Ni alloy sublayers with different Ni content the obtained CMM coatings have increased corrosion resistance in comparison with the monolayer coatings of the composing alloys.     

指甲花萃取物对镍从瓦特镀液中电沉积的影响(英文)

采用赫尔槽试验、分散能力测定法、扫描电镜、X射线衍射、能谱分析、硬度测量及交流阻抗谱,研究指甲花萃取物(主要成分为2-羟基-1,4-萘醌)对镍从瓦特镀液中电沉积(以低碳钢为基体)的影响。在温度40~50°C和pH4.5~5.0的条件下,从含60mL/L指甲花萃取物的瓦特镀镍液中得到的镀层具有良好的耐蚀性和硬度。指甲花萃取物作为瓦特镀镍液的添加剂,极大地提高了镀液的分散能力和电流效率。在最佳指甲花萃取物浓度下所得的镀镍层为晶态,结晶细致。     

Adsorption performance of nickel and cadmium ions onto brewer's yeast

The brewer's yeast was used as adsorbent for the removal of Ni(II) and Cd(II) metal ions from aqueous solution. The surface of the brewer's yeast had three main functional groups of sulfonate, carboxyl, and amine groups. The pH of solution played an important role on the uptake of metal ions, and optimum adsorption was obtained at pH 6. Acid solution (pH 3) was efficient for the desorption of Ni(II) and Cd(II) ions from loaded brewer's yeast and the desorption efficiency was higher than 90%. The rate of metal ions adsorption onto brewer's yeast was rapid with short contact time. The kinetics of the adsorption process was found to follow the pseudo‐second‐order kinetic model. Langmuir and Freundlich isotherm models were used to fit the experimental data with Langmuir isotherm model having a better fit. The maximum uptakes of Ni(II) and Cd(II) by brewer's yeast were estimated to be 5.34 and 10.17 mg/g, respectively.     

Properties of silver–antimony alloys electrodeposited from ferrocyanide–thiocyanate electrolytes

The influence of electrolysis conditions on the internal stress, microhardness, electrical contact resistance, wear resistance, roughness, and friction properties of silver–antimony alloys deposited from ferrocyanide–thiocyanate electrolytes is studied. The internal stress of the coatings depends strongly on their antimony content. Stress changes and transition from compressive to tensile stress at increased antimony content in the alloy are observed. By internal stress measurements, conclusions can be drawn concerning the homogeneity or heterogeneity of the coating, that is, whether the coating consists of one or two phases. The changes in microhardness are related to variations of the internal stress and to the phase transition. The codeposition of antimony leads to a reduction of the coating roughness. Increased Sb content of the alloy leads to an increase in the electrical contact resistance and to reduction of the contact forces and wear resistance of the coatings. At large deviations from equilibrium, an oscillating electrochemical reaction is observed leading to space-time structures on the electrode surface.     

Properties and microstructure of polyurethane resins from liquefied wood

In this article, polyurethane resins were synthesized from liquefied benzylated wood and toluene diisocyanate (TDI)–trihydromethylene propane (TMP) prepolymer (as curing agent). The relations of their segmented structure and properties of were investigated. Results indicated that polyurethane resins made from benzylated wood solution have good mechanical and thermal properties. With the increase of curing agent amount from 23.8 to 53.5%, the degree of phase segregation increased, and under experimental conditions in this article, phase transition was detected with a curing agent amount of 69.9%. After this transition, the mechanical properties of polyurethane resins were improved. Thermal history treatment can also influence microstructure and thermal stabilities of polyurethane samples. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1175–1180, 2005     

Electrochemical reduction of nickel ions from diluteartificial solutions in a GBC reactor

The electrochemical reduction of nickel ions from a dilute solution has been carried out in a gas diffusion electrode packed bed electrode cell (GBC). Particle size and electrode configuration have been found to have a significant influence on the reduction process. Electrodes with a high porosity and large pores have been found to be the best for nickel deposition. The nickel current efficiency, Ni, is reported to be dependent on the current density, volumetric flow rate, nickel and boric acid concentration, and the pH. The fall in the nickel current efficiency is caused by an increase in electrode surface pH above a certain level, caused by either high bulk solution pH or high current density, leading to possibly formation of Ni(OH)2. It has been found that under conditions of exclusively metallic nickel deposition Ni/(1–Ni) is proportional to i0.69,Q10.52,CNi0.67,CBA–0.19 and pH1.0.     

High‐retention properties for Hg(II) ions of a resin containing ammonium and pyridine groups

The metal‐ion uptake behavior of the chelating resin poly([(3‐(methacryloylamino)propyl] trimethyl ammonium chloride‐co‐4‐vinyl pyridine) has been investigated. The resin is obtained by radical copolymerization in a yield of 99.6%. The hydrophilic resin shows a high retention capacity and selectivity toward Hg(II) ions in the presence of Cu(II), Pb(II), Cd(II), Zn(II), and Cr(III) ions. A retention of Hg(II) higher than 99% is observed after 5 min. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2595–2599, 2002     

Determining the environment of transition metal ions in zeolitic catalysts: A combined computational and synchrotron-based study of nickel ions in zeolite-Y

Computer modelling techniques are used to investigate the local structure of the zeolite framework around Ni²⁺ ions in the S_I sites of Ni exchanged zeolite-Y. Our calculations show that there are pronounced inward relaxations (0.4 Å–0.6 Å) of the surrounding oxygen ions. The results allow a detailed rationalisation of recent EXAFS and diffraction studies on this zeolite.