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1.
Pingping Gao Zhiyong Xie Ouyang Chun Tao Tao Xiaobo Wu Qizhong Huang 《Journal of Solid State Electrochemistry》2018,22(7):1971-1981
The Ni-P/TiN/PTFE (poly tetra fluoroethylene) composite coatings were prepared by electroless plating method on Ti plate, which was used as bipolar plates of proton exchange membrane fuel cells (PEMFCs). The morphology, crystallographic texture, electrochemical corrosion, contact resistance, and hydrophobic property of the Ti bipolar plates with coatings were investigated. The results revealed that Ni-P/TiN/PTFE coating had a dense surface morphology, uniform distribution of composite particles. Ti with coating showed 0.48 μA cm2 of corrosion current in the simulated solution of PEMFCs and 6 mΩ cm2 of interfacial contact resistance (ICR). The hydrophobicity test showed that the coating interface was flat and the wetting angle was 112.4°. In conclusion, The Ni-P/TiN/PTFE composite coatings exhibit superior improvement in corrosion resistance, interface hydrophobicity, and conductivity to Ni-P, Ni-P/TiN, and Ni-P/PTFE coatings. The Ni-P/TiN/PTFE coating was suited for bipolar plate surface modification of bipolar plates. 相似文献
2.
Xiaokui Yang Qing Li Shiyan Zhang Hui Gao Fei Luo Yan Dai 《Journal of Solid State Electrochemistry》2010,14(9):1601-1608
In this study, a protective Ni–Co alloy coating was prepared on sintered NdFeB magnet applying electrodeposition technique.
A pure nickel coating was also studied for a comparison. The microstructure, surface morphologies, and chemical composition
of coatings were investigated using X-ray diffraction, scanning electron microscope, and energy dispersive spectroscopy, respectively.
The corrosion protection properties of coatings for NdFeB magnet in neutral 3.5 wt.% NaCl solutions were evaluated by potentiodynamic
polarization and electrochemical impedance spectroscopy (EIS) techniques. The microstructure and surface morphologies analysis
showed that the addition of cobalt element into matrix metal Ni altered the preferential orientation of pure nickel coating
from (2 0 0) crystal face for pure nickel coating to (1 1 1) crystal face for Ni–Co alloy coating, and made the surface morphologies
more compact and uniform due to the grain-refining. The results of potentiodynamic polarization test showed that compared
with pure nickel coating, Ni–Co alloy coating exhibited much nobler corrosion potential (E
corr) and lower corrosion current density (j
corr), indicating better anticorrosive properties. The long-term immersion test by dint of EIS indicated that the Ni–Co alloy
coating still presented high impedance value of 1.9 × 105 Ω cm2 with the immersion time of 576 h indicating the excellent anticorrosive properties, and corrosion protection properties of
nickel coating for NdFeB magnet practically disappeared with the immersion time of 144 h, which also indicated that the Ni–Co
alloy coating provided better corrosion protection properties for the NdFeB magnet compared with nickel coating. 相似文献
3.
A Ni-P amorphous alloy was deposited on a low carbon steel substrate via electroless plating. Further, the prepared samples were crystallized under the high temperature with a range from 200 °C to 500 °C in air for 1 h. The crystallization process was studied via XRD, AFM, and XPS, and anodic electrochemical behavior was investigated by potentiostatic methods in a 3.5 wt% NaCl solution. The experimental results indicate that the diffusion, dissolution, and enrichment of the component elements in the Ni-P alloy are essential during crystallization because the various corrosion behaviors corresponding to Ni and P are directly affected. More importantly, under the 400 °C treatment, H2PO2− was enriched in the alloy, which effectively hinders the anodic dissolution of nickel and forms a complete adsorption layer on the surface of the alloy. Our results demonstrate that P can effectively block the anodic dissolution of Ni during the corrosion process, and the crystallization process can effectively promote the surface enrichment of P to improve the corrosion resistance of the coating. 相似文献
4.
利用化学镀技术在Ti基体材料表面制备了Ni-P合金镀层和Ni-P-Cg复合镀层。利用SEM、XRD和EDS等分析了镀层的晶化过程,用差热分析仪研究了Ni-P合金镀层和复合镀层的晶化动力学,运用Ozawa、Freeman-Carroll、Achar和Coats-Redfern方法对非等温动力学数据进行了分析和比较。结果发现,复合镀层的特征温度Tm和晶化激活能E均高于Ni-P合金镀层,而热焓值|ΔH|却低于Ni-P镀层;计算出Ni-P合金镀层和Ni-P-Cg复合镀层晶化激活能分别为308.9 kJ·mol-1和412.99 kJ·mol-1、指前因子A分别为58.03 s-1和77.84 s-1,确定了Ni-P合金镀层和复合镀层晶化动力学方程。 相似文献
5.
Electrocatalytic behavior of electroless Ni-P alloys for the oxygen evolution reaction 总被引:2,自引:0,他引:2
The structural and morphological characteristics of electroless nickel phosphorous films (P content from 4.0 to 13.8 at %)
are described. Different treatments such as heat (400°C, 1 h) or electrochemical (anodizing at 0.5 V vs. SCE followed by multi-cycle
polarization) are employed and their effect on the alloys properties is analyzed using x-ray diffraction and atomic force
microscopy. Information on the performance of the as-deposited and treated electroless Ni-P coatings as anodes for oxygen
evolution reaction, in alkaline media, is taken from the steady state polarization curves and the correspondent Tafel slopes.
The data shows the importance of the deposit crystalline nature and of the electrochemical treatment on the formation of β-Ni(OH)2 and subsequently β-Ni(OOH), crucial for obtaining Ni-P films with good electrocatalytic properties.
Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 12, pp. 1427–1434.
Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes.” October 18–22,
2005, Moscow.
The text was submitted by the authors in English. 相似文献
6.
镍磷化学镀层的耐蚀性及其与磷含量的关系 总被引:3,自引:0,他引:3
用极化曲线法和交流阻抗法研究了磷含量为16.2%至23.4% (x)的不同镍磷(Ni-P)化学镀层在5%(w) NaCl溶液中的耐蚀性, 发现磷含量为21%~22% (x)时镀层的极化阻抗(Rp)出现极大值. 差示扫描量热测定也发现Ni-P合金的峰值晶化温度(Tp)在此P含量范围内存在极大值. XRD实验表明镀层呈非晶态结构. 利用描述非晶态的菱面体单元结构模型(RUSM)解释耐蚀性能和峰值晶化温度的极大值现象, 耐蚀性随P含量的变化与镀层中金属元素(Ni)和类金属元素(P)之间形成的键数有关. 通过比较镀层密度的测量值和基于RUSM的计算值, 证明了采用RUSM的合理性. 相似文献
7.
《Arabian Journal of Chemistry》2022,15(6):103815
To improve the corrosion protection properties of zinc-rich silicate coatings on steel, zirconium pretreatment loaded with (3-aminopropyl)triethoxysilane (APTES) 0.025 % (v/v) and the partial replacement of spherical zinc by flake ZnAl alloy were investigated. DC polarization and electrochemical impedance spectroscopy (EIS) show that the zirconium pre-treated layer containing APTES improves the corrosion protection of the bare steel. Zinc-rich silicate coatings containing flake ZnAl with and without pretreatment were evaluated by EIS, salt spray test and pull-off test. Pretreatment with a zirconium conversion layer reduces corrosion products and adhesion loss (from 16.53% to 12.54%) while the performance of corrosion protection significantly increased from 2003 Ω.cm2 to 2640 Ω.cm2 in comparison with the non-pretreated samples. The results show that flake ZnAl pigment (5 wt%) significantly improves corrosion resistance and prolongs the duration of cathodic protection of zinc-rich silicate coatings. 相似文献
8.
Soheila Faraji Afidah Abdul Rahim Norita Mohamed Coswald Stephen Sipaut Bothi Raja 《Arabian Journal of Chemistry》2013,6(4):379-388
The Cu–P and Cu–P–SiC composite coatings on carbon steel substrates were deposited via electroless plating. The anti-corrosion properties of Cu–P and Cu–P–SiC coatings were studied in 3.5% NaCl solution. The anti-corrosion properties of Cu–P and Cu–P–SiC coatings were investigated in 3.5% NaCl solution by the weight loss, potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques. It has been found that the shift in the corrosion potential (Ecorr) towards the noble direction, decrease in the corrosion current density (Icorr), increase in the charge transfer resistance (Rct) and decrease in the double layer capacitance (Cdl) values indicated an improvement in corrosion resistance with the incorporation of SiC particles in the Cu–P matrix. The effects of varying the SiC concentration on the corrosion resistance of carbon steel were investigated and it was found that the best anti-corrosion property of Cu–P–SiC is at 5 g L?1 SiC in the bath formulation. 相似文献
9.
氟元素是周期表中最活泼的非金属元素,有着最强的电负性,氟化物有着特殊的化学性能。关于氟化物在化学镀镍磷工艺中的应用已有报道,在镁基体上化学镀的前处理过程中,常用氢氟酸或氟化氢铵来进行活化处理;硅片表面上的化学镀也通常用HF与HNO3或HCl的混酸来活化,使硅片表面产生Si-H键。另外,如果在化学镀液中添加少量的氟化钠,则起到加速的作用[1]。对于氟化物在化学镀镍磷工艺中的报道仅限于此,未见有关氟化物在化学镀中其它作用的研究。鉴于此,本工作以氟化铵为研究对象,对其在弱碱性的条件下对化学镀液的缓冲能力、沉积速度以及所得镀层性能的影响进行了研究。 相似文献
10.
DTA in conjuction with X-ray diffraction analysis with a high-temperature camera and infrared spectroscopy was employed to
determine the mechanism of oxidation of Ni-P alloys. Amorphous Ni-P powders were obtained from a nickel(II) sulphate bath
as a nickel source and sodium dihydrophosphate(I) as a reducing agent. The crystallization product is composed of two phases:
(f.c.c.) Ni and (b.c.t.) Ni3P. The amorphous to crystalline transformation takes place in the temperature range 280–330°C. Ni3P samples were heated from room temperature to 1050°C in air atmosphere at 5°C min−1. It was found that the first stage of oxidation of Ni3P goes through the intermediate phase of Ni12P5 formation to Ni2P. Some exothermic reactions were observed. Heating runs were interrupted after each reaction for crystal structure determination
by IR spectrometry. Infrared spectra are reported and it is shown that the structure units present in the amorphous products
at about 700°C were the oxoanions PO3
− and P2O7
−. The final products of the oxidation process are NiO and Ni3(PO4)2.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Reza Arghavanian Naghi Parvini-Ahmadi 《Journal of Solid State Electrochemistry》2011,15(10):2199-2204
Pure Ni and Ni–ZrO2 composite coatings were electroplated using a Watt’s bath containing different amounts of ZrO2 to be co-deposited. Surface morphology and microstructure of the samples and particle distribution in the coatings were studied
using optical microscope, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The results
showed that the electroplated sample in the bath containing 90 g l−1 ZrO2 has the maximum particle content and the best particle distribution. Evaluation of microstructure and corrosion behavior
demonstrated that with increasing ZrO2 content in the coating, the corrosion potential shifted toward noble and positive values. This is probably due to diminishing
of the metallic surface area exposed to the solution. Higher ZrO2 contents in the coating results in lower corrosion current densities probably due to the changing of the microstructure from
coarse-grained columnar to fine-grained granular structure. The results revealed that the electroplated sample in the bath
containing 90 g l−1 ZrO2 has the best corrosion resistance. 相似文献
12.
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
13.
采用复合电沉积制备了Ni-P/(LaNi5+Al) 复合镀层, 然后将镀层浸泡在浓碱液中除铝, 成功得到多孔复合Ni-P/LaNi5电极. 通过扫描电镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)仪等技术表征了电极的表面形貌、组成和相结构. 运用电化学线性伏安扫描(LSV)、恒电位电解、电化学阻抗谱(EIS)等手段研究了电极在20%(w) NaOH溶液中的析氢反应(HER)电催化性和稳定性. 结果表明, 与多孔Ni-P 电极相比, 多孔复合Ni-P/LaNi5电极具有低的析氢过电位、高的比表面积和高的稳定性能; 多孔Ni-P/LaNi5电极的析氢反应的表观活化自由能为35.44 kJ·mol-1, 低于多孔Ni-P 的值(50.91 kJ·mol-1). 相似文献
14.
E. Onofre-Bustamante M. A. Domínguez-Crespo A. M. Torres-Huerta A. Olvera-Martínez J. Genescá-Llongueras F. J. Rodríguez-Gómez 《Journal of Solid State Electrochemistry》2009,13(11):1785-1799
The role of hydrogen peroxide in the formation of cerium conversion coatings by immersing AISI 1010 commercial carbon steel
substrates into solutions containing various concentrations of CeCl3 (0.1, 1, and 10 g L−1) has been investigated as an alternative method for their protection against corrosion. The deposits prepared from the solutions
with H2O2 consist of yellow thin and non-uniform coatings with agglomerates of small CeO2 and Ce2O3 crystallites whose sizes increased over the metallic surface as the cerium concentration was increased. Cerium pre-treatments
in the presence of H2O2 displayed layers that were rougher than those synthesized without H2O2. A comparison with the chromate conversion pre-treatment is also simultaneously carried out with the discussion of the possible
reactions involved in the different stages of process. The coating obtained from the solution containing 0.1 g in 1,000 mL
produced better corrosion resistance on the substrate than that observed for its counterparts due to the fact that the surface
was more uniformly covered by the conversion coating. The addition of H2O2 to the cerate baths improves visible roughness, corrosion resistance of the conversion coatings and bond strength because
hydrogen peroxide acts as an oxygen source during the formation of the coatings. 相似文献
15.
Anti-corrosion silica coating was prepared via the sol–gel method for AZ91D magnesium alloy using tetraethoxysilane and methyltriethoxysilane
as precursors. Silica coating was deposited on fluorinated magnesium alloy substrates by dip coating. The surface morphology
of the silica coating was characterized by scanning electron microscope (SEM). The corrosion properties were studied by electrochemical
impedance measurements and polarisation technique in 3.5 wt% Sodium chloride solution. The results showed an improvement in
the corrosion performance from these coatings. A three-factor, three-level design of experiment (DOE) with response surface
methodology including a Box–Behnken design was run to evaluate the main and interaction effects of several independent formulation
variables, which included precursor ratios MTES/TEOS (X1), sintering temperature (X3) and sol dilution (X2) which measured the volume of the diluted sol divided by the initial volume of sol. The dependent variables included the
corrosion current derived from the polarisation curve (icor = Y1) and the coating resistance derived from the Nyquist curve (Rcoat = Y2). Optimizations were predicted to yield Y1 and Y2 values of 1.57018E–7A cm−2 and 14279 Ω cm2, when X1, X2, and X3 were 3.36, 1.52 and 222, respectively. 相似文献
16.
High-electromagnetic-shielding cotton fabric (CF) was prepared using carboxyl-functionalized multiwall carbon nanotubes (MWCNTs-COOH)/nickel–phosphorus (Ni-P) electroless plating. Firstly, MWCNTs-COOH was loaded on CF used to chelate the metal catalyst followed by electroless plating to impart outstanding electrical conductivity and electromagnetic shielding properties. The intermediate MWCNTs-COOH layer not only improves the bonding strength via the chelating effect, but also can be used as a conductive material. This synergistic action of MWCNTs-COOH and Ni-P layer can work together to improve the electromagnetic interference shielding performance. The features of Ni-P/MWCNTs-COOH/CF were characterized using scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The resulting Ni-P/MWCNTs-COOH/CF fabrics show high surface resistance of 1.66 Ω sq−1 and robust electromagnetic shielding effectiveness of 40.2 dB. Furthermore, benefiting from the strong interface interaction, the as-prepared composite fabrics retain stable performances after undergoing a series of physical and chemical tests, confirming promising practical applications even under harsh conditions. 相似文献
17.
《Electrochemistry communications》2007,9(3):431-435
The performance of the SrCo0.8Fe0.2O3−δ(SCF)–La0.45Ce0.55O2−δ(LDC) composite cathodes was studied in this paper. The composite cathodes were prepared by screen-printing, and then sintered at 1200 °C for 2 h. Electrochemical impedance spectroscopy (EIS) and cathodic polarization test were carried out to investigate the electrochemical properties of the composite cathodes. The results showed that the composite cathodes had superior electrochemical performance compared to that of the pure SCF cathodes. Through optimizing the structures of composite cathodes, the cathodic overpotential of triple-layer SCF–LDC composite cathodes was only 23 mV at 0.3 A cm−2. The specific ohmic resistance, charge transfer resistance and gas phase diffusion resistance of the triple-layer SCF–LDC cathodes were the lowest for the SCF–LDC composite cathodes, and they were 0.1 Ω cm2, 0.01 Ω cm2 and 0.1 Ω cm2 respectively at 800 °C. The changes were attributable to the enlargement of triple phases boundary (tpb) and enhancement of the adhesion between electrode and electrolyte by adding LDC to the cathode material. 相似文献
18.
Madiha A. Shoeib Medhat M. Kamel Salah M. Rashwan Omar M. Hafez 《Surface and interface analysis : SIA》2015,47(6):672-680
Composite Ni–P/nano‐TiO2 coatings were prepared by simultaneous electroless deposition of Ni–P and nano‐TiO2 on a low carbon steel substrate. The deposition was carried out from stirred solutions containing suspended nano‐TiO2 particles. The Ni–P and Ni–P/nano‐TiO2 coatings before and after heat treatment were characterized by X‐ray diffraction, scanning electron microscopy and energy dispersive X‐ray spectroscopy. The micro‐structural morphologies of the coatings significantly varied with the nano‐TiO2 content. The corrosion resistance of as‐plated and heat‐treated Ni–P and Ni–P/nano‐TiO2 coatings was investigated by anodic polarization, Tafel plots and electrochemical impedance spectroscopic (EIS) studies in 3.5% NaCl solution. Ni–P/nano‐TiO2 coating exhibited superior corrosion resistance over Ni–P coating. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
19.
I. V. Petukhov N. A. Medvedeva S. S. Mushinskii M. R. Nabiullina 《Russian Journal of Applied Chemistry》2012,85(1):29-34
The growth of Ni-P coatings was studied in the “stable” electroless nickel plating solution and in the “decomposed” solution
containing in its bulk a sufficient amount of the metallic phase particles. 相似文献
20.
In this study, a series of UV-curable anticorrosive PUA coatings embedded with varying concentrations of inorganic ZnO fillers have been successfully prepared from jatropha-based polyol. The electrochemical impedance spectroscopy (EIS) and Tafel polarisation analysis revealed that increasing fillers composition lead to the improvement of the anticorrosive property of the hybrid coatings. Meanwhile, the salt spray test results were found to correlate with the EIS of Cc (F cm−2) was 2.71 × 10−9, Bode plot - 106 Ω cm2 and Tafel polarisation results 7.56 × 10−6 MPY at 3 wt% of ZnO. Physical properties of 3 wt% loading of ZnO fillers in hardness test obtained 6H which was strongly attributed to the low interfacial interaction and poor dispersion of the fillers within the polymer matrix. 相似文献