电沉积制备Ni-W-Cu新型超疏水镀层及其电沉积机理研究

Super-hydrophobic materials have attracted great interest because of their potential use in a variety of applications, such as self-cleaning, anti-polluting and anti-atmosphere corrosion. The super-hydrophobic surfaces are usually fabricated by the two-step approache，including chemically modifying the structured surfaces by organics. Poor stability of organic is the major reason of super-hydrophobic surface unsuitable for engineering application. In this project, Ni-W-Cu coating with inborn superhydrophobic effect was studied. Electrodeposition process parameters are optimized by orthogonal experiment and BP neural network system; Hydrophobic mechanism are analyzed by composition, microstructure and crystal orientation of the coating. Anti-polluting property is investigated in the artificial haze and corrosion mechanism in haze is established. Base on the special cathode interface system of electrodeposition W alloy, electrodeposition mechanism is researched by semiconductor electrochemistry technology in conjunction with the variation of cathode material and plating solution composition. By means of the above researches, a novel Ni-W-Cu coating, which have excellent performance of hydrophobic and thermal stability combine with good hardness and wear resistance, may be obtained by electrodeposition.

超疏水材料由于具有良好的防污、耐大气腐蚀性能而受到广泛的关注。常规的“两步法”制备工艺使用有机物降低表面能，有机物稳定性差成为制约超疏水表面在工程中应用的主要原因。本项目对开发无需有机物修饰的Ni-W-Cu新型超疏水镀层展开了研究：利用正交系统实验结合BP神经网络探索合适的电沉积工艺；通过分析镀层成分、微观结构、晶体取向研究Ni-W-Cu镀层的疏水机制；在人工雾箱中模拟雾霾环境，研究Ni-W-Cu镀层的污损规律，并结合污损过程中镀层表面腐蚀产物的分析，建立Ni-W-Cu镀层在雾霾环境中的腐蚀模型；引入半导体电化学的研究方法对电沉积W这一特殊的阴极界面体系展开分析，结合阴极物相和镀液成分变化，揭示Cu对W氧化物膜层以及Ni诱导W析出过程的影响机制；综合Ni-W-Cu镀层疏水机制和电沉积机理的研究结果，提出相应措施优化沉积工艺，实现对疏水性能优异、结构稳定的新型Ni-W-Cu镀层的可控制备。

超疏水材料由于具有良好的防污、耐大气腐蚀性能而受到广泛的关注。目前超疏水材料常用有机物来降低其表面能，有机物稳定性差成为制约超疏水材料在工程中应用的主要原因。本项目采用电沉积技术实现了Ni-W-Cu超疏水合金镀层的“一步”法制备，并探明了该镀层的超疏水机制和电沉积机理，具体的研究结果包括：①研究了电沉积工艺对W合金组织结构和性能的影响，并采用BP神经网络构建了工艺参数与目标性能之间的映射关系，可预测最优的目标性能以及为确定电沉积W合金的工艺参数提供参考；②阐明了Ni-W-Cu合金镀层的超疏水机制主要是利用Cu离子调控镀层的形貌和晶体结构，以获得具有的高粗糙度表面以及低表面能的（111）晶面优先生长的目标镀层。研究确定了Cu离子的添加量为0.01-0.015 mol/L时，Ni-W-Cu合金镀层呈现三维的微/纳结构（粗糙度>0.4μm）和高的晶面衍射强度比（R>4.07），具有超疏水特性（CA>150.5°）；③研究了Cu对W合金电沉积的影响过程，明晰Ni-W合金电沉积过程在阴极表面呈现连续形核特点，抑制了晶体的自由生长从而形成纳米晶。镀液中添加Cu离子将抑制W的析出，提高阴极界面反应的载流子密度，因此电沉积Ni-W-Cu合金镀层需要严格控制镀液中Cu离子的加入量。本项目所开发的超疏水镀层无需有机物修饰，并且可通过电沉积的方法实现“一步法”制备，适用于工程领域的大规模应用，同时利用电沉积技术调控镀层表面状态的方法也为开发新型的超疏水材料提供了思路和参考。