基于液体储池的疏水-超滑注液表面及其防腐蚀机制研究

The aluminum alloy is one of the key materials for developing light and high corrosion-resistant ships and marine engineering structures. Due to the coupling effect of Cl-, water erosion and other corrosion factors, the corrosion of aluminum alloys in the severe marine environment becomes a common problem, which will lead to the reduction of their safety and service life, even serious disastrous accidents. Usually, many key components are made with complex shape and work in the severe marine condition, which makes it difficult to satisfy the long term anti-corrosion demand of aluminum alloy using the single anti-corrosion coating technology. The corrosion properties of the hydrophobic-slippery liquid-infused aluminum alloy surface are investigated in the simulated marine environment. In order to reduce the loss of lubricating liquid, the lubricating liquid reservoirs consisting of large and small micro-pores are fabricated on the aluminum alloy surface. The influences of liquid reservoirs on the wetting properties and corrosion behavior are studied, and then the relationship between parameter coordination of composite dimples and consumption rate of lubricating liquid is set up. The evolution mechanism of lubricating liquid layer, namely loss-replenishment-formation, is clarified. An integrated anti-corrosion system is built on the basis of the synergistic effect of micro-pore texture and hydrophobic-slippery surface. The researched results will further improve the design theory of super slippery liquid-infused porous surface and can provide theoretical and technical support for the long term corrosion protection of aluminum alloy under severe marine environment.

铝合金是发展船舶及海洋工程结构轻量化、高耐蚀的关键材料之一。在氯离子、海水冲刷等腐蚀因素的耦合作用下，腐蚀是铝制船舶及海洋工程装备普遍存在的共性问题，会降低其安全性和使用寿命，甚至导致灾难性事故。由于许多铝合金关键部件的形状复杂性和服役工况的苛刻性，使得单一的防腐蚀涂层技术难以满足其长效防腐蚀的需求。本项目研究疏水-超滑注液铝合金表面在模拟海洋环境中的腐蚀行为，考虑到润滑液层的损耗，通过构筑大/小尺寸复合微孔织构引入润滑液储池。研究润滑液储池对疏水-超滑注液表面润湿性能和电化学腐蚀行为的影响，建立复合微孔参数配合与润滑液消耗速率之间的关系；阐明表面润滑液层消耗-补给-再形成的演化机理，建立微孔织构形貌及几何参数与疏水-注液表面协同作用的综合防腐蚀体系。研究成果将进一步完善超滑注液多孔表面的设计理论，可为苛刻海洋环境下铝合金船舶及海洋工程装备的长效防腐蚀提供理论基础和技术支持。

在海洋环境中，铝制海洋装备及工程结构遭受盐雾、浪花飞溅、水动力冲刷以及持续干/湿循环等多种腐蚀因素的耦合作用，尤其是氯离子的大量存在，会导致铝合金表面钝化膜失稳，诱发铝合金的局部腐蚀。本项目以添加疏水SiO2纳米颗粒的超疏水涂层为基础，在铝合金表面集成了激光表面织构化、阳极氧化、超疏水涂层和全氟聚醚油注入多种复合处理工艺，形成以大/小尺寸复合微孔织构为储池的疏水-注液多层涂层结构。结果表明，多种工况条件下，疏水-注液涂层的耐腐蚀性能均优于超疏水涂层，疏水-注液涂层的低频阻抗模值相对超疏水涂层提高了1个数量级，达到109 Ω·cm2。一方面，腐蚀液长时间浸泡（30d），会造成超疏水涂层的水接触角明显降低（从152°降低到120°）和耐腐蚀性恶化（腐蚀电位从-489mV负移至-767mV），而疏水-注液涂层的水接触角变化不明显，在长期浸泡过程中可以有效避免腐蚀液的渗透。另一方面，水滴连续冲击作用会造成疏水-注液表面储存的润滑液大量损失，使得表面重新恢复到疏水涂层的粗糙结构，静态水接触角增大。然而，织构化微孔的存在有利于增大表面润滑液的储存量和在表层润滑液损失时及时补充，水滴连续冲击15h未造成有织构化微孔的疏水-注液涂层润湿性和腐蚀性能的明显改变，没有明显的阴极或阳极腐蚀电流出现。冲击30h后，有织构化微孔的疏水-注液涂层的水接触角仍维持在130°左右，涂层的容抗弧直径并未出现明显降低。本项目设计了由疏水纳米颗粒屏障层、润滑液层及润滑液储池构成的多元防腐蚀体系，为保障铝合金的长效防腐蚀性能提供了新的技术思路。