环境适应性金属防护体系的构建及其环境适应机制研究

The environmental adaptability of an anticorrosion protective system plays an important role in improving corrosion resistance and elongating service-life of metals and alloys. However, currently the enviromental adaptability of a metal anticorrosion protective system is poor, which seriously limits the applications of metals and alloys. To greatly improve the corrosion resistance of metals and alloys, and further extend their applications in rigorous environments, the anticorrosion protective systems with remarkable environmental-adaptability are urgently desired. In this proposal, the construction strategies of such environmentally-adaptive anticorrosion protective systems are proposed and the corresponding environmentally-adaptive anticorrosion mechanism is expected to elucidate..First, the basic characteristics of an environmentally-adaptive anticorrosion protective system are deduced based upon the environmental factors anaysis, which are superhydrophobicity, chemical stability, thermal stability and illumination stability. Thus, improving the environmental stabilities of current superhydrophobic anticorrosion protective systems is helpful to construct the environmentally-adaptive anticorrosion protective systems. .Taking advantages of the superior properties of the rare-earth compounds that are induced by the unique electronic structures of rare-earth elements, such as intrinsical hydrophobicity, strong bonding with low-surface-energy compounds and excellent corrosion resistance, the construction strategies of the environmentally-adaptive anticorrosion protective systems are proposed: based upon the electronic structural anaysis of different rare earths, the candidate rare-earth coating systems will be figured out. Then, rare-earth oxides with certain micronanostructures will be constructed on the metals and alloys, which will be further modified with low-surface-energy compounds to strengthen the hydrophobic and protective properties. The as-constructed superhydrophobic protective systems are expected to have excellent environmental stabilities, which will be used as environmentally-adaptive anticorrosion protective systems..Natural environments tests, a variety of characterizations and quantum mechanics simulations will be used to study the environmental adaptability of the as-constructed protective systems. The composition, structure and environmentally-adaptive performance of the protective systems will be correlated. The environmentally-adaptive anticorrosion mechanism of such systems will be elucidated, which can guide the designing and optimizing of the system construction. .The achievements of this project will undoubtedly promote the much wider applications of metals and alloys, and create countless new opportunities for developing and applying of the environmentally-adaptive anticorrosion protective techniques.

金属防护体系的环境适应性对于有效防止金属腐蚀、长久发挥金属正常功能具有重要作用，然而目前的金属防护体系环境适应性差、严重阻碍金属的应用。.本项目基于对金属所处环境影响因素的分析，提出环境适应性金属防护体系应具有超疏水性、化学稳定性、热稳定性和光稳定性等基本特征。针对现有金属超疏水防护体系环境稳定性差的缺点，本项目拟利用稀土元素的特殊电子结构赋予其的本征疏水性、与低表面能物质的牢固成键及对金属的优秀防护能力构建金属防护体系：先基于电子结构分析初步确定稀土成膜体系，再在金属表面构筑特定的稀土氧化物微-纳结构，进而进行低表面能物质修饰强化疏水性能和防护性能，从而构建出具有优异环境稳定性的金属超疏水防护体系即环境适应性金属防护体系。采用自然大气环境试验并结合多种表征以及量子力学模拟研究防护体系的环境适应性行为；建立防护体系组成、结构与性能的关联，探明体系环境稳定性的内在驱动，揭示其环境适应机制。

金属防护体系的环境适应性对于有效防止金属腐蚀、长久发挥金属正常功能具有重要作用，然而目前的金属防护体系环境适应性差、不能为金属提供持久的有效防护。.针对上述问题，本项目构建了环境适应性金属防护体系并研究了其环境适应机制。主要研究内容及结果包括：(1)基于对自然大气环境因素及其作用的分析，以高强铝合金、镁合金、碳钢、铜等常见金属材料为目标防护金属，采用沸腾稀土盐溶液浴、稀土盐溶液水热、稀土溶胶-凝胶等方法在金属表面引入富含稀土镧/铈/钐（氢）氧化物的微-纳结构，进而通过硬脂酸修饰构建了稀土防护体系。(2)采用接触角（CA）、场发射扫描电子显微术（FESEM）、X射线光电子能谱（XPS）和红外光谱（IR）等技术表征了防护体系的表面润湿性、形貌、组成及价键结构，并通过实验室模拟测试考察了防护体系对水、化学介质、温度、光照、腐蚀介质等环境因素的适应性，证实构建的稀土防护体系具有超疏水性、化学稳定性、热稳定性、光稳定性。(3)借助于国防科技工业自然环境试验研究中心的万宁大气试验站（属典型的北热带湿润型海洋气候）和江津大气试验站（属典型的亚热带高温高湿酸性大气环境）研究了防护体系的长期环境适应性行为。结果显示，即使经过长期严酷的自然大气环境暴露实验，稀土防护体系的润湿性、微观结构和组成基本不变,构建的稀土防护体系具有优异的环境适应性，可以长期稳定应用于严酷的自然大气环境中。(4)基于分子力学和分子动力学理论，计算模拟了基底金属氧化物、稀土金属氧化物的亲疏水性以及不同氧化物与硬脂酸的成键能力及键合硬脂酸后表面的润湿性，明确了稀土防护体系中稀土氧化物的本征疏水性及其与低表面能物质硬脂酸的高度稳定键合是稀土防护体系具有优异的环境适应性的根本原因。 .上述结果对于发展实用性金属防护技术，促进金属材料在一些严酷环境中的应用至关重要。

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