化学镀Ni-P-Cr2O3和Ni-P-SiO2复合镀层的研究

本文对化学镀镍及化学镀镍磷基质中SiO2与Cr2O3的共沉积进行了研究.微粒在不断生长的膜层中共沉积引起了新的化学复合镀层的出现,这些复合镀层许多都具有优异的耐磨及耐蚀性能.通过选取镀层合金/复合微粒/金属基体的组分可改进镀层,获得所需的性能,以满足特别的需求.在对这些复合镀层的应用需求正在迫近与增长的同时,其市场正在迅速扩张.本文开发出了一种合适的复合化学镀镍液,并通过维氏硬度法对化学复合镀镍层进行了表征.采用动电位极化及交流阻抗法测定了镀层的Taber耐磨性能及耐蚀性能.采用SEM及XRD对复合镀层的表面形貌进行了分析.     

Wear and corrosion properties of electroless nickel composite coatings with PTFE and/or MoS2 particles

This study focuses on the effect of co-deposition of PTFE and/or MoS₂ particles on the morphology, wear, and corrosion properties of electroless nickel coating. The composite coating of EN–PTFE–MoS₂ was heat treated at different temperatures for hardness investigations. The surface morphology of coatings was characterized by scanning electron microscopy. Pin-on-disk and potentiodynamic polarization tests were used to study the tribological and corrosion properties of the coatings, respectively. Results of hardness analysis revealed that the hardness of electroless nickel coatings was increased by the heat treatment, and its maximum was gained at 400°C. Wear investigations showed that simultaneous co-deposition of the PTFE and MoS₂ particles into the nickel coating increased the wear resistance of the coating by about 30% and reduced the average value of friction coefficient to 0.25 from 0.65. Corrosion studies illustrated that simultaneous co-deposition of the PTFE and MoS₂ particles led to reduction in corrosion resistance by 10 and 5 times that of EN coating in brine and acidic solution, respectively.     

镍-磷-硫酸钡化学复合镀层的研制

在由硫酸镍31g/L、次磷酸钠22g/L、乙醇酸30g/L、乙酸钠13g/L、二甲胺0.8g/L、全氟乙基碘化铵0.1g/L及重晶石(即硫酸钡)0～25g/L组成的稳定镀液中,采用化学镀的方法在低碳钢上制备了Ni-P-BaSO4复合镀层.其表面形貌采用扫描电镜进行分析,耐蚀性以动电位极化及电化学阻抗谱测试.镍-磷合金基...     

不同材料表面镍-磷-锌盐纳米复合化学镀层性质的比较

研究比较了D310硅钢片和A3钢片表面Ni-P-Zn3(PO4)2,Ni-P-ZnSnO3和Ni-P-ZnSiO3纳米复合化学镀层的外貌和性质。用扫描电子显微镜（SEM）观察外貌：称重法测定厚度,通过10％NaCl溶液,1％H2S气体加速腐蚀试验,10％,CuSO4溶液点滴试验,饱和KCl溶液循环伏安（CV）试验,抗粘性试验及抗高温氧化试验等多种手段测定其性能。结果表明：纳米复合化学镀层的性能优于镍－磷镀层和其它微米复合镀层。     

发光化学镍复合镀层(英文)

在90℃下,采用含有25 g/L硫酸镍,20 g/L次磷酸钠、35 g/L柠檬酸钠、0～6 g/t,卤磷酸钙和15 g/t.硫酸铵的镀液(pH 5.5),制备了基于卤磷酸钙的发光化学镍复合镀层.研究了镀液pH对复合镀层的沉积速率及卤磷酸钙含量的影响.采用硬度测量、磨损测试、腐蚀试验、紫外光谱,扫描电镜和X射线衍射对复合镀层进行了表征.在最佳卤磷酸钙质量浓度(4 g/L)下所得的复合镀层含77.59%(质量分数)镍、7.58%(质量分数)磷和14.83%(质量分数)卤磷酸钙.由于卤磷酸钙是硬质粒子,随着其嵌入量的增多,复合镀层的硬度增大.在存在卤磷酸钙的条件下,化学镍复合镀层的耐磨和耐蚀性能均显著提高.     

High corrosion resistance of electroless composite plating coatings on AZ91D magnesium alloys

The process of electroless plating Ni-P on AZ91D magnesium alloys was improved. The Ni-P-ZrO₂ composite coatings and multilayer coatings were investigated based on the new electroless plating process. The coatings surface and cross-section morphologies were observed with scanning electron microscopy (SEM). The chemical compositions were analyzed by EDXS. The corrosion behaviors were evaluated by immersion, salt spray and electrochemical tests. The experimental results indicated that the Ni-P-ZrO₂ composite coatings suffered attack in NaCl solution but displayed passivation characteristics in NaOH and Na₂SO₄ solutions. The corrosion resistance of Ni-P-ZrO₂ coatings was superior to Ni-P coatings due to the effect of ZrO₂ nano-particle. The multilayer coatings consisting of Ni-P-ZrO₂/electroplating nickel/Ni-P (from substrate to surface) can protect magnesium alloys from corroding more than 1000 h for the salt spray test.     

化学复合镀Ni—P—SiO2工艺及其性能研究

在化学镀镍基础液中添加SiO2微粒进行复合镀,通过试验,探讨了Ni—P-SiO2化学复合镀的工业条件,并进行了镀层的相关性能测试。初步确定了Ni—P—SiO2复合镀的工艺参数,其中pH值为4．6左右,温度为（90±1℃）。通过性能测试可知：添加适量的SiO2微粒于配方中,所得镀层耐磨性、耐腐蚀性等性能相对于Ni—P合金镀层都有显著提高。     

Vacuum thermal treated electroless NiP-TiO2 composite coatings

Composite NiP-TiO₂ layers were prepared by simultaneous electroless deposition of Ni-P and TiO₂ on steel substrate, from a solution in which TiO₂ particles were kept in suspension by stirring. Deposits were characterized for its structure, morphology and hardness. It was found that the chemical composition of Ni-P matrix has been influenced by the incorporation of TiO₂ particles. TiO₂ particle incorporation increases with increase in their bath concentrations (0.5-2.0 g/l). An improvement (up to 20%) in microhardness was observed in both as plated and vacuum heat-treated composite coatings compared to Ni-P coatings. Electroless deposited composite coatings exhibit an amorphous structure of the nickel matrix in which crystalline titanium oxide is incorporated. Vacuum heat treatment leads to the formation of a crystalline layer in which the Ni and Ni₃P crystallites appear apart from those of the TiO₂ (anatase). Potentiodynamic polarization measurements made on these deposits in 3.5 wt.% sodium chloride solution showed decrease in the corrosion resistance for the as-plated and heat-treated composite coatings.     

Composite Ni/Al2O3 coatings and their corrosion resistance

Composite coatings Ni/Al₂O₃ were electrochemically deposited from a Watts bath. Al₂O₃ powder with particle diameter below 1 μm was codeposited with the metal. The obtained Ni/Al₂O₃ coatings contained 5-6% by weight of corundum. The structure of the coatings was examined by scanning electron microscopy (SEM). It has been found that the codeposition of Al₂O₃ particles with nickel disturbs the nickel coating's regular surface structure, increasing its microcrystallinity and surface roughness. DC and AC electrochemical tests were carried out on such coatings in a 0.5 M solution of Na₂SO₄ in order to evaluate their corrosion resistance. The potentiodynamic tests showed that the corrosion resistance of composite coating Ni/Al₂O₃ is better than that of the standard nickel coating. After 14 days of exposure the nickel coating corrodes three times faster than the Ni/Al₂O₃ coating. The electrochemical behaviour of the coatings in the corrosive solution was investigated by electrochemical impedance spectroscopy (EIS). An equivalent circuit diagram consisting of two RC electric circuits: one for electrode, nickel corrosion processes and the other for processes causing coating surface blockage, were adopted for the analysis of the impedance spectra. The changes in the charge transfer resistance determined from the impedance measurements are comparable with the changes in corrosion resistance determined from potentiodynamic measurements.     

Corrosion resistance properties of electroless nickel composite coatings

Electroless nickel (EN) composite coatings incorporated with PTFE and/or SiC particles demonstrated significantly improved mechanical and tribological properties as well as low surface energy which are desired for anti-sticking and wear resistant applications. The corrosion resistance of these composite coatings, however, has not been systematically studied and compared. This work aimed to investigate the corrosion characteristics of EN composite coatings using electrochemical measurements which include open circuit potential (OCP), electrochemical impedance spectroscopy and potentiodynamic test. The effects of the co-deposited particles on corrosion behavior of the coatings in 1.0 N H₂SO₄ and 3% NaCl media were investigated. The surface autocatalytic properties and the post-heat-treatment on coating corrosion resistance were also discussed. The results showed that both EN and EN composite coatings demonstrated significant improvement of corrosion resistance in both acidic and salty atmosphere. Ni striking substantially enhanced the corrosion resistance due to the improvement of the surface autocatalytic properties and homogeneity. Proper post-heat-treatment significantly improves the coating density and structure, giving rise to enhanced corrosion resistance.     

Effect of Annealing Temperature and Alumina Particles on Mechanical and Tribological Properties of Ni-P-Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Composite Coatings

In this study, the effect of annealing temperature and alumina particles on micro-hardness, corrosion, wear, and friction of Ni-P-Al₂O₃ composites coating is studied. The electroless nickel composite coating with various alumina particle content is deposited on a mild steel substrate. The corrosion behaviour and tribological behaviour (wear and friction) of the composite coated samples are investigated and compared with Ni-P coated samples. The micro-hardness, wear resistance, and corrosion resistance of the composite coating improved significantly after heat treatment (400 °C) and in the presence of alumina particles. The composite coating deposited with alumina particle concentration of 10 g/L in an electroless bath and heat treated at 400 °C shows excellent results compared to Ni-P, as-deposited Ni-P-Al₂O₃ coating and coatings heat treated at different annealing temperature (200 °C, 300 °C, and 500 °C). Microstructure changes and composition of the composite coatings due to incorporation of alumina particles and heat treatment are studied with the help of SEM (scanning electron microscopy), EDX (energy dispersive X-ray analysis and XRD (X-ray diffraction analysis).     

化学镀镍磷合金镀液中杂质颗粒度对镀层耐蚀性的影响

化学镀镍磷合金具有很多独特的理化性能,然而由于成本较高限制了其应用。为降低化学镀镍的成本,采用工业级药品配制镀液。研究了镀液中杂质颗粒度对镀层耐蚀性的影响。随着镀液中颗粒度的降低,镀层耐蚀性明显提高,说明化学镀对镀液中的有较高的复合率,因此必须严格控制镀液中的杂质颗粒度。     

化学镀镍-磷基纳米复合镀层的研究进展

综述了近年来国内外化学镀Ni-P基纳米复合镀层的研究进展,概述了纳米TiO2,SiO2,Al2O3、SiC、金刚石等对复合镀层耐磨性,耐蚀性的影响,介绍了纳米稀土氧化物在化学复合镀中的应用.     

化学镀Ni-P-石墨复合镀层的特性

与化学镀Ni-P镀层比较,化学镀Ni-P-石墨复合镀层的机械性能得到了改进,适合于工程方面的应用。Ni-P-石墨复合镀层是从含有硫酸镍、次磷酸镍、丁二酸、表面活性剂和稳定剂的镀液中制备的。当镀液中石墨含量为15g/L时,镀层中石墨的复合量最大。采用维氏硬度测试仪、泰伯磨耗实验机、交流阻抗和SEM等手段对复合了石墨颗粒的Ni-P化学镀层进行了测定,其硬度,耐磨、耐蚀性随镀层中石墨含量的增加而增强。     

(Ni-P)-钛酸钾晶须化学复合镀层的制备与耐蚀性

采用化学复合镀方法,在低碳钢基体上成功的制备出不同质量浓度钛酸钾晶须的(Ni-P)-钛酸钾晶须复合镀层。结果表明,当镀液中钛酸钾晶须为6 g/L时,镀层沉积速率及钛酸钾晶须的共析量达到最大值,用交流阻抗法研究了镀层在5%NaCl溶液中的耐腐蚀性能,发现复合镀层的极化电阻均比Ni-P合金镀层的大,钛酸钾晶须的加入显著提高了复合镀层的耐腐蚀性能。     

表面活性剂对Ni-P-高岭土复合镀层耐蚀性能的影响

以低碳钢为基体,通过在化学镀液体系中加入高岭土粒子获得Ni-P-高岭土复合镀层,研究了表面活性剂种类及用量对复合镀层性能的影响.实验过程中采用金相显微镜和极化曲线分别对复合镀层的表面形貌和耐蚀性能进行测试.结果表明:当采用聚乙二醇和十二烷基苯磺酸钠时,复合镀层的耐蚀性能较好,而采用三乙醇胺和十六烷基三甲基溴化铵时,镀层...     

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°.     

纳米粉体在化学复合镀中的应用

向化学镀液中加入纳米粉体，使纳米粉体与金属共沉积，可得到性能各异的纳米化学复合镀层。对Ni—P基化学复合镀的沉积机理进行了推测。从高硬度耐磨性、自润滑性、抗高温氧化性、耐腐蚀性等方面，介绍了各种纳米化学复合镀层的研究进展。对纳米粉体的分散性问题进行了探讨，并对纳米化学复合镀层的前景提出了展望。     

铝硅镁合金化学镀镍

研究了在铝硅镁合金基体上直接化学镀镍和在基体上电镀铜后再化学镀镍2种工艺.采用扫描电子显微镜分析技术,盐雾法、锉刀法等试验方法比较了2种工艺所得镀层的表面形貌,耐蚀性和结合力,结果表明:2种样品的镍镀层都具有很好的耐蚀性及较好的结合力,对铝硅镁基体具有良好的保护作用.与铝硅镁合金直接化学镀镍相比,铝硅镁合金基体电镀铜后化学镀镍所得的镍层组织更致密,结合力更好,耐蚀性更优异.     

硬铝合金化学镀镍耐蚀机理

通过对铝合金组织，化学镀镍各溶液成分，化学镀镍镀层性质，铝合金化学镀镍工艺的分析，找出了影响铝合金化学镀镍耐蚀性的关键因素是镀层厚度和孔隙率，铝合金基体状态，前处理工艺，化学镀镍工艺参数，溶液成分，镀后处理等均会影响镀层的孔隙率，所以对铝合金化学镀镍耐蚀性等级要求高的行业在使用该工艺时要控制全过程工艺要点，否则就达不到预期的目的。