铝合金表面超疏水性与海洋大气腐蚀行为关系研究

Based on the following two aspects, superhydrophobic surface (SHS) is proposed to improve the corrosion resistance of aluminum alloy substrate: on one hand, the formation of thin electrolyte layer (TEL) is expected to be suppressed due to the low adhesion between SHS and water; on the other hand, even if TEL were formed on SHS temporarily and partially, the corrosion can be alleviated due to the special solid-liquid interface (i.e., the formed air pockets on the interface). However, till now, there are few reports to reveal the correlation between superhydrophobicity and ocean atmospheric corrosion behaviors. A series of basic scientific questions, such as the correlation between the surface structures and condensation, the characteristics and mechanisms of electrochemical reaction under TEL for SHS, the influence of enviromental factors on corrosion behaviors, remain unknown. To make clear of these questions, SHS on LY12 alluminum alloy substrate is to be designed, and the condensation as well as corrosion behaviors under the influence of typical enviromental factors will be measured. It is hoped that this project will discover the detailed mechanim of atmospheric corrosion resistance for SHS and provide scientific basis for developing practical atmospheric corrosion resistant technology.

本项目基于以下两点认识，提出利用超疏水表面进行铝合金海洋大气腐蚀防护：第一，超疏水表面有利于抑制金属表面薄液层的形成；第二，即使薄液层在超疏水表面局部能够暂时形成，超疏水表面特殊的固液界面（固液界面存在的"气囊"）也能极大的缓解腐蚀的发生。然而，迄今为止，表面超疏水性与海洋大气腐蚀行为的相关性研究尚未展开，其中的一些基础科学问题，例如超疏水表面粗糙结构与水分凝聚行为的关系、薄液层下超疏水表面电化学反应特性和机理、环境因素对腐蚀行为的影响都尚待深入研究。本申请课题就是针对上述问题，以LY12铝合金为样品，从表面粗糙结构设计、水分凝结与腐蚀实验监测、及相关机理分析等方面研究金属表面超疏水性与海洋大气腐蚀行为之间的关系，揭示超疏水表面的抗大气腐蚀机理，为开发实用的抗海洋大气腐蚀技术提供科学依据和思想方法。

本项目在金属铝等基体上构筑了不同类型的超疏水涂层，并对超疏水表面水分凝聚、超疏水样品在氯化钠溶液中腐蚀行为进行了研究。主要研究内容和结果如下：.（1）超疏水涂层制备。利用铝与水、次氯酸钠、硝酸银等的化学反应，在铝基表面构筑了不同种类的超疏水涂层，制备超疏水涂层依次简记为H-SHS、N-SHS、A-SHS。与传统的超疏水制备方法相比，这些方法都具有各自的特点。例如，由于所用试剂为水，制备H-SHS的方法具有绿色环保的特点；由于生成氧化层的阻隔效应，N-SHS具有较好的腐蚀防护效果；制备A-SHS的方法具有突出的推广性，可适应一系列活泼金属（例如Al, Fe, Co, Mo, Mg, Zn, Sn, Pb, Cu等）。.（2）超疏水表面水分凝聚行为研究：利用体视显微镜或接触角测量仪实时观测超疏水表面空气中水分的凝聚行为或外加水滴的冷冻行为。可以发现，与疏水表面或亲水表面相比，超疏水表面能显著减缓水分或液滴在铝基表面的凝聚、冷冻。.（3）超疏水涂层的腐蚀防护效果。利用动电位极化曲线对比研究了H-SHS与盐酸刻蚀法制备的超疏水样品的腐蚀行为差异，结果表明，由于生成氧化层的阻隔效应，H-SHS（1.03 nA/cm2）样品的腐蚀电流密度远小于盐酸刻蚀法制备的超疏水样品（67.8 nA/cm2）。在研究N-SHS涂层腐蚀行为的实验中，特别注意腐蚀过程中样品宏观、微观形貌及表面成分的变化。这些方法与分析拓宽了超疏水表面腐蚀行为的研究思路。相关研究成果在投稿到Applied Surface Science时，受到审稿人的盛赞（The discussion about the corrosion resistance in NaCl is excellent …I really appreciate the analysis toward the anti-corrosion in NaCl solution）。.上述研究成果已发表SCI论文13篇、核心期刊论文2篇，申报国家发明专利2项。