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1.
Electrodeposited zinc–nickel alloy coatings have been widely adopted for surface treatment of automobile body steel sheet for high corrosion resistance. The corrosion behavior of the coatings has been related with the components of nickel, and the zinc–nickel alloy passive coatings have much higher corrosion resistance than that of zinc–nickel alloy coatings. In the present paper, the corrosion resistance behavior of the zinc–nickel alloy coatings obtained by new process and formulation has been studied by means of the electrochemistry test and neutral salt spray test. And it is discovered that the properties of corrosion resistance of zinc–nickel alloy passive coatings were better than that of zinc passive coatings, Cadmium passive coatings and alloys of electrodeposited cadmium–titanium. The components of corrosion productions, in terms of X‐ray diffraction (XRD), are mainly ZnO, ZnCl2 · 4Zn(OH)2 and small quantity of 2ZnCO3· 3Zn(OH)2. The component of zinc–nickel alloy coatings has been investigated with Glow Discharge Optical Emission Spectrometry (GDA‐750). And it is found that as the thickness of zinc–nickel alloy coatings increases, the component of zinc increases from beginning to end, but the peak value of nickel appears and an enrichment of nickel in the coatings comes into being. Because the electrodeposited zinc–nickel alloy coatings exhibit different alloy phases as a function of their alloy composition, in this paper, the crystal structure changing with the different component of nickel has been studied in terms of XRD. The result shows that electrodeposited zinc–nickel alloy has different phases: α‐phase, a solid solution of zinc in nickel with an equilibrium solubility of about more than 79% nickel; γ‐phase, an intermediate phase with a composition Ni5Zn21; η‐phase, a solid solution of nickel in zinc with less than 5% nickel; and δ‐phase (Ni3Zn22) appeared from η‐phase to α‐phase with increasing content of nickel. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
2.
Katsuhiko Shinyama Yoshifumi Magari Tadayoshi Tanaka Hiroshi Nakamura Toshiyuki Nohma Ikuo Yonezu 《Research on Chemical Intermediates》2006,32(5):419-429
The effects of electroless nickel plating of a hydrogen-absorbing alloy on the cycle characteristics of a nickel-metal hydride
battery were investigated. The cycle life was improved by employing an electroless nickel-plated hydrogen-absorbing alloy
for the negative electrode, which retained the same high-rate level and low-temperature characteristics compared to a cell
using a non-plated hydrogen-absorbing alloy. The electroless nickel-plated hydrogen-absorbing alloy provided better electrochemical
characteristics when its surface was partly and tightly covered by nickel particles under optimal electroless plating conditions. 相似文献
3.
采用一锅法制备了钨酸镍与氧化锌复合材料(NiWO_(4)-ZnO),并对其进行了形貌表征、元素分析及比表面积测试,构筑了一种吲哚美辛电化学传感器。研究发现,NiWO_(4)-ZnO复合材料修饰玻碳电极对吲哚美辛表现出较高的检测灵敏度,在最优的实验条件下,吲哚美辛浓度与氧化峰电流成正比,在250~1082 pmol/L范围内呈现良好的线性关系,线性相关系数为0.9970,检出限为66.6 pmol/L。吲哚美辛电化学传感器应用于实际样品中吲哚美辛的测定,回收率为95.1%~98.3%,相对标准偏差为2.3%~3.8%,该传感器可用于药物分析领域。 相似文献
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In this paper several aspects involved in the chlorination of a Zn 48% wt.–Cu alloy between 250 and 500 °C are investigated. The starting temperature for the chlorination of the alloy is determined, which is different from those of pure metals. Analysis of the chlorination thermogravimetric curves and reaction products reveal that there are interactions between reactants and products during the reaction, and that volatilization of ZnCl2 is diminished during the alloy chlorination. Metallic copper is detected at intermediate stages of the chlorination, and this element, which is not present in the initial sample, appears during the chlorination reaction. An oxidation–reduction type reaction between copper chlorides and metallic zinc is proposed to explain the behaviour observed. The occurrence of this reaction at room temperature was confirmed in separate experiments. At the beginning of the reaction, formation of zinc oxichloride was detected that is being formed from the zinc oxide layer that covers the alloy surface. According to the results obtained, a reaction mechanism is presented for the alloy chlorination. 相似文献
5.
研究以5 Br PADAP为显色剂,用混合线性分析分光光度法同时测定铜、锌、镍。在pH8.2的硼砂 盐酸缓冲溶液中,Cu2 、Zn2 、Ni2 分别与5 Br PADAP形成稳定的配合物,其吸收光谱相互重叠。用一种新的数学模型,即混合线性分析进行光谱分辨,各组分的纯光谱则用最小二乘法求得。讨论了反应条件、测量波长的选择等因素的影响。铜、锌、镍的标准回收率分别为95.0%~102.5%、94.2%~101.3%和96.2%~104.2%。应用于铝合金中铜、锌、镍的同时测定。 相似文献
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Raney Ni催化剂是石油化学工业用量最大的催化剂之一,通过急冷技术将其晶态结构转变为非晶态结构,能够提高加氢活性.但非晶态合金热稳定性差、比表面积小限制了这类催化材料的工业应用.通过加入少量稀土元素,使非晶态 Ni 晶化温度提高200 K以上; 通过加入Al再碱抽Al,使非晶态Ni比表面积增加100倍以上; 通过加入功能助剂调节非晶态Ni的加氢选择性、增加抗酸碱腐蚀性和磁性,从而形成了系列非晶态Ni加氢催化剂 (商品名为 SRNA).其中,SRNA-1 用于药物中间体加氢; SRNA-2用于葡萄糖加氢制山梨醇; SRNA-3用于汽、柴油吸附脱硫; SRNA-4用于己内酰胺加氢精制; SRNA-5 用于苯甲酸加氢中替代Pd/C催化剂,使后者的用量减少了50%. 相似文献
8.
建立火焰原子吸收光谱法测定锌合金中镁含量。选用10 mL盐酸溶液(1+1)溶解样品,加入5 mL质量浓度为100 g/L的LaCl3溶液,以消除铝对镁的化学干扰,在选定的仪器工作条件下进行测定。结果表明,镁的质量浓度在0~1.238 mg/L范围内与与吸光度具有良好的线性关系,相关系数为0.999 4,线性方程为Y=1.086 4X+0.018 5,方法测定下限为0.010 mg/L。样品测定结果的相对标准偏差为1.61%~3.45%(n=6),加标回收率为91.3%~94.7%。该方法准确度高,精密度好,满足锌合金中镁含量的日常检测要求。 相似文献
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Ismail M.M. Rahman Yoshiaki Furusho Zinnat A. Begum Ronald Bruening Hiroshi Hasegawa 《Microchemical Journal》2011,98(1):103-4854
Separation of trace levels of lead from concentrated-matrix electroless nickel plating (ENP) waste solutions is required to meet the increasingly stringent environmental regulations. A solid phase extraction (SPE) system using a molecular recognition technology (MRT) gel was used for the selective separation of trace levels of lead (Pb) from the waste discharge of ENP operations, followed by subsequent analysis with inductively coupled plasma optical emission spectrometry (ICP-OES). Two SPE-MRTs, AnaLig® Pb-01 and AnaLig® Pb-02, packed in 3 mL polypropylene cartridges were used to treat the synthetic metal-waste solutions that were used to simulate the typical metal mixture in ENP bath waste. The fortified solutions contained 100-1000 μg L− 1 of Pb in an HNO3 matrix with pre-added Ni, Cu and other interfering elements (1000 mg L− 1). After the sample treatment, the SPE-MRT cartridges were washed with water and 0.1 M nitric acid, followed by elution with 0.03 M EDTA. The matrix elements (e.g., Ni, Cu) were completely removed at the washing step, while the ‘captured’ Pb was quantitatively eluted, as determined by ICP-OES measurements. The detection limit of the proposed method was 2.6 μg L− 1. ‘Real’ samples from commercial ENP operations were used to assess the validity of this method, and almost quantitative Pb recovery was observed. The excellent Pb selectivity of the SPE-MRT system indicates the potential of the proposed technique for trace-level Pb separation from the Pb-containing high matrix aqueous waste discharge. 相似文献
11.
The effect of component concentrations in electroless nickel plating solution on topography and microrelief of Ni-P coatings 总被引:1,自引:0,他引:1
I. V. Petukhov 《Russian Journal of Electrochemistry》2008,44(2):147-157
Topography and microrelief of Ni-P coatings deposited by electroless plating from solutions with different composition are examined as a function of concentrations of nickel and acetate ions, solution pH, and stabilizing additives, namely, PbCl2 and thiourea. The coating growth involves the formation of surface spheroids of which a large percentage are strongly extended in the substrate plane and grow by the layered-growth mechanism. In terms of this mechanism, the changes in the topography and microrelief of coatings and also in the spheroid size as a function of the composition of electroless nickel plating solutions are explained. In solutions studied, the rates of formation of new two-dimensional layers and their propagation in the substrate plane are assessed. As the concentration of hydrated nickel ions in solution decreases, spheroids less extended in the substrate plane are formed and grow probably by the normal growth mechanism. The size distribution of spheroids is obtained and the reasons for the partial formation of spheroids with sizes deviating from those predicted by the normal law are analyzed. 相似文献
12.
Power compensation differential scanning calorimetry (DSC) has been employed to detect and analyse precipitation reactions in an Al-1.3Mg-0.4Mn and an Al-1.3Mg-0.4Mn-0.07Cu alloy in which very small amounts of precipitate, less than 0.3 at.%, are expected to form. Due to the very small heat effects, baseline instability and drift significantly interfere with the measurements. After repeated experiments and careful baseline correction it is demonstrated that in the Cu containing alloy, ageing at 170 °C causes the appearance of two endothermic effects: for 2 days ageing a small dissolution effect appears at about 230 °C, whilst for 7 and 21 days ageing a dissolution effect peaking appears at about 300 °C. The temperature range of the latter is consistent with S phase dissolution. 相似文献
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J. -I. Toei 《Chromatographia》1987,23(5):355-360
Summary A liquid chromatographic procedure for separating nickel and zinc has been developed. Xylenol orange, which is one of the
sensitive and commercially available color-forming agents, was used as a component of the mobile phase. The two ions could
be separated on weak anion-exchange gels within 10 min. The procedure was suitable for the determination of nickel and zinc
in relatively pure solutions with fairly high sensitivity. The described liquid chromatographic analysis would be also potentially
applicable for any aqueous sample containing trace levels of metal cations at 1–10 ppm. 相似文献
15.
Tao Long-Xiang Zhang Feng-Mei Zheng Lu-Bin 《Reaction Kinetics and Catalysis Letters》1996,57(1):99-104
Nickel-deposited USY zeolite samples were prepared by a method of impregnation with a solution of nickel naphthenate in benzene followed by drying and calcination. The interaction between nickel and zeolite was investigated by XPS after calcination, steaming and hydrogen reduction. 相似文献
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An additive-free Watts type bath containing micron- and nano-SiC particles (1 μm and 20 nm respectively), as well as ultrafine-WC
particles (200 nm), was used for the production of pure Ni and nickel matrix composite electrocoatings under both direct and
pulse current conditions. Moreover, nickel nanocrystalline deposits were obtained from a Watts type bath containing small
amounts of 2-butyne-1,4-diol, in order to investigate the combined advantages of additives and pulse technique on the properties
of the deposits. The influence of the variable electrolysis parameters, the particle size and the organic additive concentration
on the surface morphology, the structure and properties of the deposits were discussed. It has been proved that the application
of pulse electrodeposition affects drastically the structural characteristics and properties of the deposits and under well-defined
conditions could lead to the preparation of nanostructured materials with improved mechanical properties.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 6, pp. 802–811.
The text was submitted by the authors in English. 相似文献
19.
A novel type of glassy carbon electrode modified with magnetic carbon-coated nickel nanoparticles (C-Ni/GCE) was fabricated
and the electrochemical properties of brucine were studied using it. The carbon-coated nickel nanoparticles showed excellent
electrocatalytic activity for the redox of brucine and an enhanced electron transfer rate. The electrochemical behavior of
brucine on the C-Ni/GCE was explored by cyclic voltammetry (CV), and a redox mechanism for brucine was proposed. A series
of electrochemical parameters were calculated for brucine by CV and controlled-potential electrolysis. The C-Ni/GCE showed
good sensitivity, selectivity and stability, and was applied to determine the concentration of brucine. The differential pulse
voltammetry (DPV) response of the C-Ni/GCE showed that the catalytic current was linear with the concentration of brucine
in the range of 4.7 × 10−8 to 2.4 × 10−4 mol l−1, with a correlation coefficient of 0.998. The detection limit was 1.4 × 10−8 mol l−1. 相似文献
20.
硝酸锌与三种氨基酸配合行为的相化学研究 总被引:7,自引:0,他引:7
用半微量相平衡法研究了Zn(NO~3)~2-His/Met/Phe-H~2O在25℃及全浓度范围内的溶度性质,构置了体系的溶度图及饱和溶液的折光指数-组成图,发现并制备了未见文献报道的固液同组成三元化合物Zn(His)(NO~3)~2.(1/2)H~2O与Zn(Met)(NO~3)~2.(1/2)H~2O和固液异组成三元化合物Zn(Met)~3(NO~3)~2.H~2O,Zn(Phe)(NO~3)~2.H~2O与Zn(Phe)~3(NO~3)~2.H~2O。通过化学分析、元素分析、IR光谱、X射线粉末衍射、TG-DTG等对其组成、结构及热稳定性进行了研究。 相似文献