(Ni-W-P)-SiC复合镀层的脉冲电沉积及其耐蚀性

研究了(Ni—W—P)—SiC复合镀层的脉冲电沉积工艺及耐蚀性。结果表明：(Ni—W—P)—SiC复合镀层的脉冲电沉积速率比直流电沉积大,脉冲镀层的耐蚀性优于直流镀层和1Cr18Ni9Ti不锈钢;脉冲频率和占空比对镀层的沉积速率、镀层成分以及镀层的耐蚀性都有较大的影响。     

电刷镀纳米复合镀层接触疲劳性能研究

利用电刷镀技术制得了含纳米颗粒的复合镀层。测试了它们的显微硬度和接触疲劳寿命，考察了载荷和退火处理(400℃保温30min)对镀层疲劳寿命的影响，并与镍镀层进行了对比。结果表明，在镀液中加入纳米颗粒显著提高了镀层的显微硬度。载荷为60N和140N时，n—Al2O3纳米颗粒的加入提高镀层的疲劳寿命，而n—ZrO2纳米颗粒降低镀层寿命。镀层寿命随载荷的增加而降低。载荷为140N时．退火后的n—Al2O3／Ni和n—ZrO2／Ni镀层寿命高于镍镀层，n—Al2O3／Ni镀层的疲劳寿命降低，而n—ZrO2／Ni镀层寿命大幅度提高。失效分析表明，疲劳裂纹在滚道表面和亚表层同时萌生，并沿镀层内部扩展；镍镀层的断口有明显塑性变形特征，n—ZrO2／Ni镀层呈脆性剥落，退火后其断口塑性变形特征明显。     

代铬镀层--Ni-W、Ni-W-B非晶态合金镀层性能研究

通过在浓硝酸、ω=5％NaCl溶液c=1mol/L H2SO4溶液中的浸渍试验,研究了不同基体上的Ni-W非晶态合金镀层的耐蚀性;通过测定在ω=5％ NaCl溶液及c=1mol／1．的HNO3溶液、H2SO4溶液、HCl溶液中的阳极极化曲线,研究了Ni-W非晶态合金镀层薄膜本身的耐蚀性;采用线性极化方法对Ni—W—B非晶态合金镀层在u=5％ Na—Cl溶液、c=1mol／L H2SO4溶液及HNO3溶液中的腐蚀速度进行了测定,并测定了以上2种非晶态合金镀层的硬度与耐磨性.结果表明．非晶态的Ni—W、Ni-W-B镀层比晶态镀层的耐腐蚀性能要好．而Ni—W—B非晶态合金镀层比Ni—W非晶态合金镀层的耐蚀性能又明显提高;经热处理后,Ni—W—B非晶态镀层的硬度值明显高于Ni—W非晶态镀层,耐磨性能都提高了1倍以上Ni—W、Ni—W—B非晶态镀层极有望成为一种比较好的代铬镀层。     

超声脉冲电沉积镍–氧化锆–氧化铈纳米复合镀层

在超声场中采用脉冲沉积法制备了Ni–ZrO2–CeO2二元纳米复合镀层。镀液组成和基础工艺条件为:氨基磺酸镍300 g/L,H3BO3 30 g/L,NH4Cl 5 g/L,润湿剂0.15 g/L,ZrO2 20 g/L,CeO235 g/L,温度(45±2)°C,pH 3.8±0.1,时间2 h。研究了平均电流密度、占空比和脉冲频率等对Ni–ZrO2–CeO2复合镀层中纳米颗粒含量的影响。采用静态浸泡法研究了不同脉冲参数下制备的纳米复合镀层在10%H2SO4溶液中的耐腐蚀性。结果表明,在平均电流密度4 A/dm2、占空比0.4、频率1 000 Hz条件下脉冲电沉积时,Ni–ZrO2–CeO2复合镀层中纳米颗粒的含量最高,表面最细致。超声波的引入使复合镀层中纳米颗粒的含量有少许降低,但能细化晶粒,提高复合镀层的耐腐蚀性能。Ni–ZrO2–CeO2复合镀层的耐腐蚀性优于相同工艺条件下制备的纯Ni、Ni–ZrO2以及Ni–CeO2镀层。     

二元镍基合金镀层析氢性能的研究

通过电镀、化学镀及复合镀的方法,制备了Ni—S、Ni—P、Ni—Mo、Ni—W、Ni—Co、Ni—WC及Ni—ZrO2等一系列二元镍基合金镀层及复合镀层,并通过阴极极化曲线测试,比较了它们的析氢性能。从元素电子结构及元素电负性方面对合金元素的作用进行理论分析,初步探讨了镍基合金镀层的电催化机理。     

专利实例

电镀镍及其合金两则　2 0 0 35 0 1 无硼酸镀镍电解液一种无硼酸的镀镍电解液组成如下 :Ni SO4·6H2 O 2 0 0～ 360 g/L;Ni Cl2 · 6H2 O 30～ 90 g/L;Ni3 ( C6H5O7) 2 · 1 4H2 O2 4～ 42 g/L;C6H8O7· H2 O1 2～ 2 1 g/L;以水为溶剂。溶液的 p H值为 3～ 5。(日本专利 ) JP2 0 0 1 1 72 790 - A2 ( 2 0 0 1 - 0 6- 2 6)2 0 0 35 0 2 　　保护性 Ni- W合金镀层电解液提出了获得高耐蚀性 Ni- W合金镀层的方法和电解液。电解液组成和工艺条件如下 :硫酸镍 2 5～35 g/L;氯化镍 3～ 5 g/L;钨酸钠 8～ 5 0 g/L;柠檬酸钠 2 5～ 1 5…     

Ni-ZrO2复合镀层的结构表征

采用复合电沉积制备Ni-ZrO2复合层。采用X-射线衍射检测ZrO2的加入对镍镀层结构的影响,如衍射峰的强度、金属电沉积时晶粒的择优取向。测试表明,Ni和ZrO2各自在特定的角度分别出现其独特的衍射特征峰,互不干扰,镀层中ZrO2含量增高,衍射强度变强。ZrO2在镀层的掺杂,镀层的晶粒尺寸由29.29 nm降至21.78 nm,镀层晶粒细化。     

MoS_2对Ni~(2+)离子及H~+离子还原速度影响的研究

众所周知。在电沉积金属复合镀层中,以金属镍为基质金属的复合镀层应用较为广泛。本文在Watts镀镍电解液中悬浮MoS_2微粒,应用复合电镀技术制备出性能优良的减摩复合镀层,实验中发现,该复合镀层与电解液的pH值关系极大,必须在低pH值条件下才能沉积出质量合格的Ni—MoS_2复合镀层,这一特殊性反映出,MoS_2对电极过程是有影响的。为此,本研究着重探讨了MoS_2对Ni~(2+)离子及H~+离子还原反应速度的影响。实验中分别测定了Watts镀镍电解液和悬浮3g/LMoS_2的Watts镀镍电解液的总阴极极化曲线     

电沉积制备Pb-WC-ZrO2复合镀层的工艺及性能研究

通过在氟硼酸铅体系中加入适量的固体颗粒,制得Pb-WC—ZrO2复合镀层。主要研究了电沉积工艺条件（搅拌速度、电流密度及电沉积时间）对Pb-WC—ZrO2复合镀层成分、表面形貌和结合力的影响,从而得出最佳固体微粒加入量及工艺条件为：20～30g/L的ZrO2,20～30g／L的WC,搅拌强度500～600r／min,电流密度2～3A／dm^2,时间2h。在ZnS04-H2S04体系中进行的阳极极化曲线测定表明,此复合镀层适于作惰性阳极材料;电子探针成分分析表明,复合镀层中主要成分是Pb和O还舍有一定量的Zr和W元素,说明Zn和WC都沉积到镀层中;X-射线衍射分析表明,镀层中Pb的衍射峰最强,其次为WC的衍射峰,在衍射图中也存在ZrO2的衍射峰但比较微弱。     

钨酸钠含量对S135钢电沉积铁–镍–钨合金镀层的影响

利用钨酸钠通过电沉积在S135高强度钻杆用钢表面制备了Fe–Ni–W合金镀层。采用极化曲线测量以及结合力、显微硬度、厚度等测试研究了Fe–Ni–W合金镀层的耐蚀性和机械性能,并利用X射线衍射分析了其结构。结果表明,在其他条件相同(即Fe SO4·7H2O 30 g/L,Ni SO4·6H2O 40 g/L,C6H8O7·H2O适量,添加剂YC-2 1~5 g/L,pH 6.5,温度70°C,电流密度4 A/dm2,时间1 h)的情况下,改变钨酸钠的质量浓度(20~60 g/L),所得镀层的性能也不相同。当钨酸钠质量浓度为50 g/L时,镀层各种性能指标均达到最佳,镀层中主要含有Ni17W3和Fe Ni3等物相。     

Morphological, structural, microhardness and electrochemical characterisations of electrodeposited Cr and Ni-W coatings

This study examines the corrosion of electrodeposited Cr and of two electrodeposited Ni-W coatings in 0.1 mol L⁻¹ NaCl solution, as well as the influence of heat treatment on the crystallographic structure and microhardness properties of these coatings. Physical characterisation is carried out using scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray analysis. Electrochemical characterisation is carried out using both the potentiodynamic linear polarization technique and open circuit measurements during long-term immersion tests. The corrosion products on the coating surfaces are characterised by ex situ Raman spectroscopy. As-electrodeposited Ni-W samples do not present defects, and the surface evolves from fine globular grains to rough polycrystalline morphology with decreasing electrodeposition current density. All the studied coatings corrode in the chloride medium and the corrosion is non-uniform for the Ni-W coatings. Raman analyses carried out after the immersion tests reveal Cr₂O₃ and Cr(OH)₂ corrosion products on the Cr coating surface, and Ni(OH)₂, NiO and WO₃ corrosion products on the Ni-W coating surfaces. Ni, Ni₄W and Ni-W phases are formed after heat treatment of the Ni₈₆W₁₄ coating at 600 °C. Although all the annealed Ni-W layers are cracked, their microhardness increases as the annealing temperature increases, suggesting that Ni-W coatings are potential substitutes for chromium in industrial applications in which good microhardness properties and stability at temperatures higher than 100 °C are required.     

Fabrication of Ni-W-B4C composite coatings and evaluation of its micro-hardness and corrosion resistance properties

Boron carbide (B₄C) particles were embedded in nickel-tungsten (Ni-W) coatings by pulse current electrodeposition technique. Physical properties of the composite coatings were studied by XRD, SEM, EDS and Vickers micro-hardness instrument. Corrosion protection of the deposited films was investigated utilizing potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS). Results exhibited that the addition of B₄C nanoparticles into the Ni-W alloy can significantly improve the surface morphology and the micro-hardness of the composite coatings. The corrosion resistance of Ni-W-B₄C nanocomposite is much better than Ni-W alloy deposit, especially when the concentration of B₄C nanoparticles is 2?g/L in plating bath, the obtained Ni-W-B₄C composite coating has the best surface morphology, the highest micro-hardness and the excellent corrosion resistance.     

复合电沉积(Ni-W)-PTFE工艺的研究

通过电沉积方法制得了(Ni-W)-PTFE复合镀层并研究了钨酸钠质量浓度和PTFE复配液质量浓度对复合镀层的成分及性能的影响。结果表明,钨酸钠质量浓度提高,镀层中钨的质量分数以及镀层的耐蚀性都有提高,PTFE复配液质量浓度提高会使镀层的摩擦系数降低,使镀层自润滑性得到改善。     

化学镀(Ni-P)-WC纳米微粒复合镀层的研究

采用化学镀的方法制备(Ni-P)-WC纳米微粒复合镀层,研究了镀液中WC纳米微粒的添加量对镀层中微粒含量的影响,通过扫描电镜观察了(Ni-P)-WC纳米微粒复合镀层的表面形貌。研究发现,纳米微粒镀层的硬度随着镀层中WC纳米微粒含量的增加而提高。通过测量(Ni-P)-WC纳米微粒复合镀层在NaCl溶液中的开路电位曲线和电化学阻抗谱,发现其耐蚀性能要优于合金镀层。     

衬套基材电沉积镍-钨-硼合金镀层的研究

在衬套用W70钨-铜合金板表面电沉积镍-钨-硼合金镀层,并研究了镍-钨-硼合金镀层的结构、耐磨性及表面形貌。结果表明:镍和钨属于诱导共沉积。电沉积过程中,钨和硼进入镍的晶格中,能够抑制镍晶粒的生长,从而细化晶粒,大大提高了镍-钨-硼合金镀层的硬度和耐磨性。镍-钨-硼合金镀层呈现出小山状颗粒形貌,表面较为均匀、致密,属于Ni₁₇W₃面心立方结构,摩擦因数约为0.12,磨损率约为3.72×10^-6 mm³·N^-1·m^-1。     

Effect of titania particles preparation on the properties of Ni–TiO2 electrodeposited composite coatings

In this paper, the effect of titania particles preparation on the properties of Ni–TiO₂ electrocomposite coatings has been addressed. Titania particles were prepared by precipitation method using titanium tetrachloride as the precursor. The titanyl hydroxide precipitate was subjected to two different calcinations temperatures (400 and 900 °C) to obtain anatase and rutile titania particles. These particles along with commercial anatase titania particles were separately dispersed in nickel sulfamate bath and electrodeposited under identical electroplating conditions to obtain composite coatings. The electrodeposited coatings were evaluated for their microhardness, wettability, corrosion resistance, and tribological behavior. The variation of microhardness with current density exhibited a similar trend for all the three composite coatings. The composite coating containing anatase titania particles exhibited higher microhardness and improved wear resistance. However, the corrosion resistance of the composite coating containing commercial titania powder was superior to that of plain nickel, Ni–TiO₂ composite coatings containing anatase and rutile titania particles. The poor corrosion resistance of these composite coatings was attributed to the higher surface roughness of the coatings. This problem was alleviated by incorporating ball-milled titania powders. The composite coatings with higher surface roughness were modified with a low surface energy material like fluoroalkyl silane to impart hydrophobic and superhydrophobic properties to the coatings. Among these coatings, Ni–TiO₂–9C coating exhibited the highest water contact angle of 157°.     

碳纤维表面电沉积合金(复合)镀层初步研究

采用电化学沉积的方法,在聚丙烯腈基碳纤维表面制备了Ni–Fe、Fe–P、Ni–B合金及Fe–Cr2O3复合镀层。结果表明:碳纤维表面的预处理对合金(复合)镀层与基底间的结合力有重要影响。扫描电子显微镜结果显示,未经活化处理的碳纤维表面镀层与基体的结合力差,表面有裂纹;表面活化处理后的镀层细致,均匀,结合力好。通过改变与合金元素相应的电解质浓度可改变镀层中合金元素的含量,获得具有不同合金含量的、与碳纤维结合紧密的合金或复合镀层。     

Nanocrystalline Ni–Co alloy coatings: electrodeposition using horizontal electrodes and corrosion resistance

Nanocrystalline Ni–Co alloy coatings containing 0–45 wt% Co were electrodeposited using horizontal electrodes in a modified Watts bath. Different techniques including scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, microindentation, and potentiodynamic polarization were used to characterize the alloy coatings. Properties of the alloy coatings were investigated as a function of the cobalt ion concentration (Co²⁺) in the bath. It was observed that the alloy codeposition exhibits anomalous behavior. Co content in the alloy coatings increases with increasing Co²⁺ in the bath and with electrolyte agitation. Morphology and grain size of alloy coatings are greatly affected by Co content. By increasing Co content, surface morphology of the alloy coatings changes from pyramidal to spherical. Microhardness of the alloy coatings increases with increasing Co content mainly due to decreasing grain size that follows the Hall–Petch relation. In addition, Ni–17 wt% Co alloy exhibits better corrosion resistance compared to pure Ni and other Ni–Co alloy coatings. The higher corrosion resistance of Ni–17 wt% Co coating is discussed based on its phase structure, grain size, and preferred orientation.     

Electrochemical corrosion behavior of composite coatings of sealed MAO film on magnesium alloy AZ91D

Protective composite coatings were prepared on magnesium alloy AZ91D by micro-arc oxidation (MAO) treatment plus a top coating with sealing agent using multi-immersion technique under low-pressure conditions. The corrosion resistance of AZ91D alloy with composite coatings was superior evidently to that with merely MAO film. SEM observations revealed that the sealing agent was integrated with MAO film by physically interlocking; therewith covered uniformly the surface as well as penetrated into pores and micro-cracks of MAO film. The anti-corrosion properties in 3.5% NaCl solution of the composite coatings were evaluated by using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. Based on the results of chronopotentiometric (E ∼ t) and EIS measurements for long time immersion in 3.5% NaCl solution, appropriate equivalent circuits for the composite coatings system were proposed. It follows that due to the blocking effect of the sealing agent in pores and cracks in MAO film, the composite coatings can suppress the corrosion process by holding back the transfer or diffusion of electrolyte and corrosion products between the composite coatings and solution during immersion.