水机过流面仿生抗冲蚀涂层及其冲蚀特性研究

The slurry erosion wear of hydraulic turbine transition parts is always a common problem to be solved urgently in hydroelectric engineering. Polymer coatings show a preferable application foreground in protecting and rapid restoring of hydraulic turbine transition parts. The research showed that the crack initiation and propagation which was impacted by sand particles was the main cause of the failure and damage of the polymer coatings. Therefore, decreasing impact stress and preventing the crack growth is an effective approach to improving the anti-erosion property of polymer coatings. This project is based on current achievement of anti-erosion mechanism of coupling bionics surface in desert and marine environment. According to biomimetic principles, the bionic design and microcapsule technique were introduced to prepare the anti-erosion polymer coatings. The main idea and contents in this project includes three aspects: One, a compound structure system with reducing wear and improving anti-impact property was designed according the macroarchitecture of native lizard teguments. Two, according to the mollusk shells compound structure made of a calcium carbonate nacreous layer and an organic compound with clear crack prevention characteristics, through application of the idea of microcapsule, the self-preventing crack growth function, together with toughening effect, was added to this anti-erosion polymer coating. Three, the anti-erosion characteristics and mechanism of the biomimetic polymer coating are studied.

水机过流件表面的泥沙冲蚀磨损是水电水利工程中急待解决的突出问题，采用聚合物涂层保护和快速修复过流面显示出良好的应用前景。研究表明，粒子周期性冲击导致的材料裂纹及其扩展是聚合物涂层损伤的主要原因。因此，降低冲击应力和阻止裂纹扩展是进一步提高涂层抗冲蚀性能的有效途径。本项目借鉴沙漠和海洋冲蚀环境中典型生物体表耐冲蚀磨损耦合机制研究的最新成果，开展水机过流面仿生聚合物抗冲蚀涂层研究，主要研究思想与研究内容有三个方面：一、模仿沙漠蜥蜴体表层合结构，研究聚合物涂层缓冲抗磨仿生结构构筑的理论和方法；二、模仿海洋贝壳碳酸钙珍珠层/有机质复合组织结构具有自身止裂功能，引入微胶囊复合改性设计，仿生构建聚合物涂层材料自身的止裂增韧机制；三、研究仿生聚合物抗冲蚀涂层的冲蚀特性和冲蚀机理。

水机过流面冲蚀磨损一直是我国水电水利工程中的技术难题。本项目借鉴沙漠和海洋冲蚀环境中典型生物体表耐冲蚀磨损耦合机制，开展水机过流面仿生聚合物抗冲蚀涂层研究，具体开展了以下几方面的工作：.（1）模仿沙漠蜥蜴抗冲蚀体表结构，开展了聚合物涂层整体结构的层合设计及模型优化。包括抵御切削、犁削和铲削的刚性面层，通过变形缓释沙粒冲击能量并降低冲击应力的中间弹性层以及对各层起有机连接作用的过渡层等构造。考虑了单粒子（尺寸，密度、冲击速度、入射角等）冲击，推导出了涂层应力-应变数学模型，并对涂层各子层材料弹性参数进行优化设计。.（2）模仿贝壳珍珠层的结构，构建了表面自身止裂保护的刚性层，通过表面刚性层止裂增韧以达到涂层的自我保护目的。制备了脲醛树脂包覆环氧树脂微胶囊，详细考察了合成条件对微胶囊粒径、表面形貌、囊芯与囊壁质量比等影响。制备了埋置微胶囊与粒子共混填充聚合物复合材料；考察了不同因素对复合材料缺口冲击强度和动态压缩特性等影响；分析了复合材料冲击损伤与其静动态特性的相关性。.（3）根据理论模型分析，在经过优化匹配的刚性层、弹性层厚度与弹性模量参数指导下，制备了仿生聚合物抗冲蚀涂层。在旋转圆盘冲蚀实验台上同步进行仿生聚合物涂层和非仿生聚合物涂层的含沙流冲蚀实验，对比考察了涂层冲蚀性能。全面研究仿生聚合物涂层的冲蚀损伤特性，分析了涂层冲蚀特性与涂层结构与材料组织（层合结构、止裂增韧）之间的联系。绘制了仿生聚合物涂层的冲蚀特性曲线（冲蚀率随粒子冲击速度、粒子尺度、入射角及水中含沙浓度等变化的曲线）并分析了涂层的冲蚀磨损机理。.（4）在南方水电设备公司协作下，在水轮机叶轮上涂覆了仿生聚合物抗冲蚀涂层，仿生聚合物抗冲蚀涂层保护的涡轮，维修周期明显延长。