工艺参数对Ni-SiC纳米复合镀层硬度的影响

为了提高结晶器铜板的使用寿命,采用电沉积的方法得到了Ni-SiC纳米复合镀层。采用单因素实验法对影响电镀层硬度的阴极电流密度、SiC纳米微粒添加量、pH及温度等进行了研究。结果表明,Ni基SiC纳米复合电镀工艺参数均对复合镀层的硬度有影响。对Ni-SiC纳米复合镀层的表面形貌进行了测试,确定最优工艺条件为8g/L SiC纳米微粒,Jκ为3A/dm2,pH为4.0,θ为30℃。纳米复合镀层的硬度与纯镍镀层相比有明显提高。     

纳米复合电镀层的研究

纳米复合电镀是获得纳米复合镀层的一种新工艺,能够很好地提高镀层的性能。纳米复合电镀层比一般的复合镀层具有更好的耐磨性、耐蚀性和更高的硬度。本文介绍了纳米粒子复合电镀层的结构及具有耐磨性能、耐腐蚀性能、自润滑性能、抗高温氧化性能和催化性能等不同功能的纳米复合电镀层,并对纳米复合电镀的发展前景进行了展望。     

脉冲电沉积工艺参数对结晶器铜板Ni-Al_2O_3复合镀层硬度的影响

采用脉冲电沉积技术在结晶器铜板表面制备了Ni-Al_2O_3复合镀层,并研究了脉冲电沉积工艺参数对其硬度的影响。结果表明:Ni-Al_2O_3复合镀层的硬度随占空比的增大(20%~100%)先增大后减小,随平均电流密度的增加(2~15A/dm~2)同样是先增大后减小;在占空比70%、平均电流密度9A/dm~2的条件下,获得纳米微粒的质量分数为3.76%的Ni-Al_2O_3复合镀层,其硬度达到最大值5.5GPa。复合镀层中纳米微粒的质量分数升高,有利于提高复合镀层的硬度。     

SiC纳米颗粒增强型复合镀层的研究进展

SiC纳米颗粒作为增强相添加到复合镀层中,可提高镀层的综合性能。分析了SiC纳米颗粒对镀层的表面形貌、显微硬度、耐磨性和耐腐蚀性等性能的影响机理,讨论了SiC纳米颗粒浓度、电流密度和搅拌速度等工艺参数对制备复合镀层的影响,阐述了不同电沉积方式对制备复合镀层的影响,指出在SiC纳米颗粒增强型复合镀层研究中尚需解决的若干问题。     

纳米材料在复合电沉积中的应用

综述了纳米复合镀层(包括高硬度耐磨纳米复合镀层,耐腐蚀、装饰性复合镀层,耐高温氧化复合镀层和具有电接触功能的纳米复合镀层等)的研究现状。对纳米微粒与金属的共沉积机理———吸附机理、力学机理和电化学机理以及纳米复合镀层的结构特点进行了概述。指出了纳米复合电沉积技术存在的问题及今后的发展方向。     

汽车半轴用钢电沉积Ni-SiC复合镀层的耐磨性

在汽车半轴用钢(40Cr钢)上电沉积Ni-微米SiC复合镀层和Ni-纳米SiC复合镀层。研究了两种Ni-SiC复合镀层的硬度和耐磨性,并研究了纳米SiC的质量浓度对Ni-纳米SiC复合镀层的硬度和耐磨性的影响。结果表明:Ni-纳米SiC复合镀层的耐磨性优于Ni-微米SiC复合镀层的耐磨性;纳米SiC增多有利于提高Ni-纳米SiC复合镀层的硬度,改善耐磨性;当SiC粒径为70nm、质量浓度为14g/L时,Ni-纳米SiC复合镀层的硬度最高,达到5 486MPa,耐磨性最好。最优Ni-纳米SiC复合镀层的磨损率明显低于40Cr钢的磨损率,摩擦因数是40Cr钢的3/4,能有效改善汽车半轴用钢的耐磨性。     

镍基氧化铝纳米微粒复合电镀的研究现状

以Al2O3纳米微粒为复合材料的复合电镀是一种取代镀硬铬的极有价值的复合表面技术。Al2O3微粒与镍金属共沉积可明显提高镀层的硬度、耐磨性与耐蚀性。主要阐述了Al2O3纳米微粒与金属镍共沉积的工艺条件对沉积速率和镀层性能的影响。并且指出Al2O3纳米微粒复合镀镍中关键问题是如何提高复合镀层中纳米微粒的含量及镀层形貌对镀层性能的影响,以寻找控制镀层表面形貌的条件。     

含纳米粉镀液的电刷镀复合镀层试验研究

应用电刷镀技术制备了含有纳米SiC粉的镍基复合镀层，对该复合镀层的显微硬度和摩擦学性能进行了测试，并讨论了主要工艺参数对这些性能的影响规律。测试结果表明：纳米SiC粉的加入可以一定程度的提高复合镀层的硬度。快镍复合纳米SiC镀层的摩擦因数低于快镍镀层的摩擦因数。镀液中纳米SiC粉和添加剂浓度增加时，复合镀层的摩擦因数有降低趋势。与快镍镀层相比，快镍复合纳米SiC镀层的耐磨性有较大幅度的提高。还采用光学显微分析(OM)和电子探针(EPMA)研究了对该复合镀层的表面形貌、组织和元素分布特点，并提出了纳米SiC粉与镍共沉积的机理。     

Ni／nano—diamond复合镀层结构和性能研究

用电刷镀技术制备含纳米金刚石粉的复合镀层。试验研究了复合镀层中纳米金刚石对镀层显微结构、力学性能及耐磨性能的影响。结果表明,纳米金刚石的弥散强化作用可有效改善镀层的生长,减小内应力,提高镀层的显微硬度。含纳米金刚石粉的复合镀层在室温,高负荷下具有优良的抗疲劳和抗磨损性能,其耐磨性是纯镍镀层的四倍。     

Ni-W/SiO2纳米复合镀层的制备与性能研究

采用电沉积的方法制备了Ni-W/SiO2纳米复合镀层,研究了镀液中SiO2纳米微粒的添加量和电流密度对镀层中微粒含量的影响,通过扫描电镜观察了Ni-W/SiO2纳米复合镀层的表面形貌.研究发现,纳米复合镀层的硬度随着镀层中SiO2纳米微粒含量的增加而提高.通过测量Ni-W/SiO2纳米复合镀层在NaCl溶液中的阳极极化曲线发现纳米复合镀层的耐蚀性能要优于合金镀层.     

镍基纳米复合镀层的研究进展

综述了镍基纳米复合镀层的研究现状。阐述了复合镀层的沉积机理、纳米微粒在复合镀层中的作用机理、纳米微粒在镍基镀液中的分散以及镍基纳米复合镀层的种类和性能。指出了纳米复合镀技术研究中存在的问题和发展方向。     

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。     

“Effect of nano-ZnO particles on the corrosion behavior of alkyd-based waterborne coatings”

A nano-composite was formed by incorporating nano-ZnO in a specially developed alkyd-based waterborne coating to different loading levels. The nano-ZnO based composite coatings were applied on mild steel substrate by dipping. The coated panels were subjected to various test environments like salt-spray, humidity, UV and mechanical tests like scratch and abrasion. The improvement in electrochemical performance and mechanical properties of the composite coatings were evaluated using various analytical techniques. FTIR technique was used to investigate the interaction between nano-ZnO particles and the polymer functionalities. Differential scanning calorimetry (DSC) was done to study the curing behavior of nano-composite coatings. SEM and AFM were used to investigate dispersion of nano-ZnO particles and the changes in the surface behavior of the coatings before and after exposure to the test environment. The result showed that, with increase in the concentration of nano-ZnO there was an improvement in the corrosion resistance, UV resistance and mechanical properties of the coatings indicating the positive effect of addition of nano-ZnO particles in the coatings.     

Sol-enhanced electroplating of nanostructured Ni-TiO2 composite coatings—The effects of sol concentration on the mechanical and corrosion properties

Novel sol-enhanced Ni-TiO₂ nano-composite coatings were electroplated by adding a transparent TiO₂ sol into the traditional electroplating Ni solution. It was found that the structure, mechanical properties and corrosion resistance of the nano-composite coatings were largely determined by the sol concentration. The higher sol concentration in the plating electrolyte led to a higher content of TiO₂ nano-particles in the coating matrix. The coating prepared at the sol concentration of 12.5 mL/L had the best microhardness, wear resistance and corrosion resistance. Adding excessive sol to the electrolyte changed the surface microstructure, caused cracking on the coating surface and deteriorated the properties. It was demonstrated that the corrosion resistance of the composite coatings is determined by two factors: surface microstructure and incorporation of TiO₂ nano-particles.     

连铸结晶器保护渣稳态润滑作用的简化数学分析

根据Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，并作若干简化假设，建立了描述连铸结晶器内保护渣润滑作用的数学模型．结合凝固规律可以预测结晶器保护渣物理性能和连铸工艺条件对润滑层厚度、保护渣消耗量、拉坯阻力和结晶器内传热的影响．     

黑Cr-C纳米复合电沉积工艺中电流密度的确定

研究了电流密度对黑Cr-C纳米复合镀层组织及性能的影响.通过扫描电镜(SEM)观察复合镀层的表面形貌,并测定了镀层的显微硬度.结果表明,黑Cr-C纳米复合镀层显微硬度最高达10.5 GPa,镀层中微粒的体积分数最高达8.12%,电沉积复合电镀最佳电流密度为100 A/dm2.     

占空比对Ni-WC纳米复合镀层耐蚀性及硬度的影响

采用脉冲电沉积法在304不锈钢基体上制备出Ni-WC纳米复合镀层,并研究了占空比对Ni-WC纳米复合镀层耐蚀性及硬度的影响。结果表明:随着占空比的增大,Ni-WC纳米复合镀层的平均晶粒尺寸先减小后增大,硬度先增大后减小;当占空比为50%时,Ni-WC纳米复合镀层的平均晶粒尺寸最小,耐蚀性最好,硬度最大。     

电沉积镍基和铜基纳米复合镀层耐蚀性的研究

通过腐蚀浸泡实验、阳极极化曲线和电化学阻抗谱等测定,探讨了Ni-W-(Si3N4,Al2O3)和Cu-(Al2O3,SiO2)纳米复合镀层的耐蚀性能;通过综合分析,对比添加不同柱子所得镀层的性能,直观地得到添加不同粒子的镍基和铜基纳米复合镀层耐蚀性能的差异.结果表明:Ni-W-Si3N4、Ni-W-Al2O3纳米复合镀层致密度较高,耐蚀性能较好,Cu-Al2O3、Cu-SiO2纳米复合镀层耐蚀性能较差.     

Effect of nano-ZnO particles on the corrosion resistance of polyurethane-based waterborne coatings immersed in sodium chloride solution via EIS technique

Nano-composite coatings were formed by incorporating 3 wt% nano-ZnO in a polyurethane-based waterborne coating. The nano-ZnO based composite coatings were applied on standard phosphated steel panels by cathodic electrodeposition. The electrodeposited nano-composite coatings were then baked for 20 min at 165 °C. To investigate the corrosion resistance of the coatings, the coated panels were immersed in 3.5 wt% NaCl solutions for 2880 h (120 days). The improvement in corrosion performance of the composite coatings was evaluated using electrochemical impedance spectroscopy technique. It was found that the films containing nano-sized ZnO particles show a corrosion resistance of 2 orders of magnitude higher than that of the neat films.     

WC的质量浓度对Ni-WC纳米复合镀层耐蚀性及硬度的影响

采用脉冲电沉积方法在304不锈钢基体上制备出Ni-WC纳米复合镀层。研究了WC的质量浓度对Ni-WC纳米复合镀层性能的影响。结果表明:随着WC的质量浓度的增加,Ni-WC纳米复合镀层的耐蚀性先增强后减弱,硬度先增大后减小;当WC的质量浓度为30g/L时,Ni-WC纳米复合镀层的耐蚀性最好,硬度最大。