硅藻壳改性水性复合润滑涂层的制备与性能研究

树脂基复合润滑涂层的出现有效解决了严苛工况下零件表面的润滑难题。根据分散介质的种类，树脂基复合润滑涂层可分为有机溶剂型和水性。其中水性复合涂层以绿色环保等优势，正逐渐成为研究热点。然而现有的水性复合润滑涂层的力学及摩擦学性能，相较传统有机溶剂型涂层仍存在差距。因此继续开发高性能水性复合润滑涂层具有重要的科学意义。

为此，本论文以水性聚酰胺酰亚胺（WPAI）树脂为粘结剂，聚四氟乙烯（PTFE）为固体润滑剂，生物质基多孔材料硅藻壳（DFs）为功能性增强填料，在确定高性能组分的基础上，通过合理优化设计，开发出一种兼具优异力学及摩擦学性能的新型绿色水性复合润滑涂层。具体如下：

分析了DFs与WPAI树脂的相容匹配性。DFs的亲水性使其均匀分散在WPAI树脂中；DFs的多孔结构起到物理铆定WPAI树脂的作用；DFs与WPAI树脂的化学键合进一步增强了界面结合力。因此DFs-5@WPAI复合涂层表现出优异的热稳定性（T₁₀=473 ℃）和机械强度（硬度=0.39 GPa）。

探究了PTFE与WPAI树脂的最佳复合方式。对不同配比的WPAI/PTFE水性复合润滑涂层的结构、力学及摩擦学性能进行系统的探讨和对比。发现当WPAI与PTFE的质量比为45：55时，相应的复合涂层的摩擦系数和磨损率分别比纯WPAI涂层降低了41%和25%。此时最大限度发挥了WPAI树脂的粘结作用和PTFE的自润滑作用。

在确定WPAI和PTFE最佳配比的基础上，引入DFs对WPAI/PTFE基复合涂层的力学及抗磨损性能进行深度优化。系统分析了DFs含量变化对复合涂层机械性能及摩擦学性能的影响，并详细探讨了相应的增强机理及失效机制。当DFs的添加量为5 wt%时，相应的复合涂层硬度为0.36 GPa，相比WPAI/PTFE复合涂层提高了49%；同时其磨损率为4.29×10^-5 mm³∕(N⋅m)，相较WPAI/PTFE复合涂层降低了29%。

本论文不仅为高性能新型水性复合润滑涂层的设计提供了新的思路，还拓展了硅藻壳在摩擦学领域的应用。本项工作符合可持续发展的理念，有助于推动涂层领域向低碳环保的方向发展。

The resin-base composite lubricating coatings has effectively solved the problem of lubrication on the surface of parts under harsh working conditions. According to the types of dispersion medium, the resin-base composite lubricating coatings can be divided into organic solvent-based and water-based coatings. Among them, water-based coating is green, eco-friendly, and has many other advantages, which is becoming a research hotspot. However, the mechanical and tribological properties of current water-based composite coating are inferior to those of traditional organic solvent-based composite coating. Therefore, it is of great significance to continue to develop high-performance water-based composite lubricating coating.

Therefore, this work used water-based polyamide imide (WPAI) resin as the binder, polytetrafluoroethylene (PTFE) as the solid lubricant, biomass-based porous materials diatom frustules (DFs) as the functional reinforcement filler to develop a novel green water-based composite lubrication coating, which has excellent mechanical and tribological properties. After determining the basic components, this coating showed excellent performance via the optimal design. The main contents are as follows:

The compatibility of DFs and WPAI resin was analyzed. The hydrophilicity of DFs makes them evenly dispersed in the WPAI resin. The porous structure of DFs plays the role of physical riveting and fixing WPAI resin. In addition, the chemical bonding cooperation between DFs and WPAI resin further enhances the interfacial interaction. Therefore, DFs-5@WPAI composite coating exhibits excellent thermal stability (T₁₀=473 ℃) and superior mechanical strength (hardness=0.39 GPa).

The optimal composite method of PTFE and WPAI resin was investigated. The structure, mechanics, and tribological properties of WPAI/PTFE water-based composite lubricating coatings with different proportions were systematically discussed and compared. It is found that when the mass ratio of WPAI to PTFE is 45: 55, the friction coefficient and wear rate of the composite coating are 41% and 25% reduced than that of the pure WPAI coating, respectively. This proportion maximized the cohesive action of WPAI resin and the self-lubricating action of PTFE.

Based on determining the optimal ratio of WPAI and PTFE, DFs were introduced to further optimize the mechanics and wear resistance of WPAI/PTFE composite coating. The effect of DFs content on the mechanical and tribological properties of the composite coating was analyzed, and the corresponding enhancement and failure mechanisms were discussed in detail. When the DFs content is 5 wt%, the hardness of the composite coating is 0.36 GPa, which is 49% higher than that of the WPAI/PTFE coating. At the same time, the wear rate is 4.29×10^-5 mm³∕(N⋅m), which is 29% reduced.

In summary, this work not only provides a new idea for the design and preparation of high-performance water-based composite lubricating coating, but also expands the application of diatom frustules in the field of tribology. This work is in line with the concept of sustainable development and promotes the development of the coating field in the direction of low-carbon and environmental protection.

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