基于氧化铈低表面能特性的新型超疏水陶瓷涂层制备与性能研究

The application development of superhydrophobic surface is significantly hampered by its poor wear-resistance and durability. This problem can be possibly resolved by replacing the organic hydrophobic material with more wearable and stable inorganic hydrophobic materials, such as rare-earth oxides. This project proposes a plasma electrolytic oxidation (PEO) method to fabricate an inorganic ceramic superhydrophobic coating with cerium oxide micro-/nano-structure on light alloys. Firstly, by adjusting techniques and methods of the PEO processing, controllable fabrication of the PEO coating is realized. With both material characterization and plasma monitoring, the forming mechanism of the cerium oxide micro-/nano-structured coating is studied. Secondly, the relationship between surface morphology and wetting behavior is investigated. The wear resistance, corrosion resistance, and superhydrophobic durability of the coating at specific environments are evaluated systematically. Based on the above, the superhydrophobicity and robustness of the coating are synergistically optimized. Finally, combining experimental methods and the First-principles theory calculation, the influence of hydrocarbon small molecules' spontaneous adsorption to the surface energy of cerium oxide is studied to clarify the hydrophobic mechanism of cerium oxide. Both the surface energy and surface morphologic factors are introduced into the generalized superhydrophobic theoretic model to illustrate the structure-performance matching mechanism. This project can not only provide theoretical basis but also technical support to the design and fabrication of the new-type superhydrophobic surface.

耐磨耐久性能不足是制约超疏水表面应用发展的瓶颈问题。采用更加耐磨和稳定的稀土氧化物等无机疏水材料替代有机疏水材料则有望从根源上解决这一难题。本项目拟采用等离子体电解氧化（PEO）法，在轻合金表面一步制备具有氧化铈微纳结构的无机陶瓷超疏水涂层。通过对工艺方法的调节实现涂层的可控制备，并以材料表征辅以等离子体监测的方法，对氧化铈微纳结构涂层的生长机制进行研究；探明不同形貌结构下涂层的润湿性行为演变规律，并研究涂层在磨损、腐蚀和特殊环境条件下的超疏水耐久性能，实现涂层超疏水性能和鲁棒性（robustness）的协同优化；结合实验研究和第一性原理计算，研究碳氢小分子自发性吸附对氧化铈表面能变化的影响，明确氧化铈的疏水机理，并将材料表面能与涂层形貌结构参数共同引入广义超疏水理论模型，阐明涂层的超疏水构性适配机制。本项目能够为新型超疏水界面材料的设计与制造提供理论依据和技术支持。

本项目基于等离子体电解氧化（PEO，又称微弧氧化MAO）法在铝合金表面制备了具有氧化铈纳米结构的陶瓷复合涂层，形成了具有微纳复合粗糙度的涂层界面结构，表面润湿性研究发现涂层经过在空气中的暴露处理后发生了由亲水到超疏水的润湿性转变。涂层的超疏水特性使得其表面可以呈现液滴弹跳和滴状冷凝行为，并具有优良的防腐蚀性能。对涂层在摩擦磨损条件下的超疏水鲁棒性研究表明，涂层具备了一定程度的超疏水机械稳定性，但这依然受到PEO涂层本身耐磨性的制约。通过第一性模拟计算分析了碳氢小分子在氧化铈表面的吸附行为，并讨论了其对于涂层表面疏水性变化规律的影响。为构建具有更佳表面耐磨性的PEO涂层结构，采用微纳片层结构材料掺杂的方法显著提升了PEO涂层材料的耐磨和防腐性能，并阐释了相关的PEO涂层组成结构与性能优化的耦合机制。本项目为基于PEO方法和氧化铈低表面能特性的超疏水涂层材料制备提供了理论支撑与技术支持。项目采用的PEO复合涂层制备技术与性能优化方法具有简单、高效、低成本的优势，未来有望在海洋防腐、汽车工业等领域中获得应用。