核壳纳米复合润滑材料研究进展

Research Progress of Composite Lubricating Material with Core-Shell Structure

润滑材料作为提高机械系统服役寿命的关键材料,已成为高端装备技术发展的重要组成部分。长期以来,探索低摩擦、高耐磨一体化的高性能固体润滑剂是摩擦学材料领域的重要研究方向。通过功能纳米材料的化学定向结合制备具有润滑与耐磨功能的核壳复合粒子,将对提高材料的摩擦学性能具有重要意义。软硬相粒子的结构与分散性是影响润滑材料摩擦学性能的重要因素。传统机械混合法易产生材料的相分离或分散不均匀等问题,已无法满足苛刻工况对材料低摩擦和耐磨损的技术要求。核壳纳米材料由于其复合体系间稳定的界面结合力和可控的表面化学状态,可以实现苛刻工况下润滑材料的长寿命、低摩擦和良好的服役可靠性,在润滑材料领域中具有广阔的应用前景。核壳复合材料在结构调控与形态分布等方面具有较强的灵活性,核壳界面的相互作用可以为可控性制备及形成结构稳定且易于均匀分散的核壳复合体提供重要基础。在结构调控方面,近年来重点开展了核壳纳米材料的组成、结构演变、尺度、形态以及分散性等研究。在制备方法方面,自组装、溶胶-凝胶、微乳液聚合、软硬模板等技术手段对于提高核壳粒子的热力学稳定性和界面作用具有不同的优缺点。在摩擦学机理方面,大量研究揭示了摩擦过程中核壳粒子的动态结构变化规律,通过薄膜润滑理论、渗透层作用机制、第三体抗磨机理、滚动轴承作用和自耗机理等论述,多角度阐明了核壳结构纳米粒子的摩擦学作用机制。在润滑材料的应用方面,各类功能型核壳纳米粒子在提高润滑油功能添加剂、高分子涂层以及高分子复合材料的性能发挥方面起到了重要作用。研究表明,具有特征结构优势的核壳纳米粒子对提高润滑材料的摩擦学性能和承载能力具有重要意义。本文结合国内外的研究现状,系统综述了核壳复合材料的常见类型、制备方法、结构调控机理、摩擦磨损机制以及在润滑材料中的应用,展望了未来核壳纳米材料在润滑与失效机理、精准复配与性能优化、核壳结构自修复机理等方面的研究方向。

Lubricating materials,as a crucial matter to improve the service life of the mechanical system,have become an important part of the development of high-end equipment technology.For a long time,it has been an important research direction in the field of tribological materials to explore high-performance solid lubricant with low friction and high wear resistance.Core-shell composite particles with the properties of lubricating and wear-resisting can be prepared as high-performance solid lubricants by the chemical directional combination of the functional nanomaterials,which is of great significance to improve the tribological properties of materials. The structure and dispersion of soft and hard phase particles are the key means to improve the tribological properties of lubricating materials.Due to phase-separation and non-uniform dispersion,the traditional mechanical-mixing method cannot meet the service requirements of low friction and wear-resistant materials under harsh working conditions.Because of the stable interfacial bonding force and regulatable surface chemical state between the composite systems,the core-shell nanomaterials can realize the long life,low friction and operational reliability of lubricating materials under harsh working conditions,and have promising prospects in the field of lubrication materials. The core-shell nanomaterials have the advantage of presenting greater flexibility in structural regulation and morphological distribution.The interfacial interaction of the core-shell structure provides an essential basis for the controllable preparation of the core-shell particle and the formation of core-shell complex with stable structure and uniform dispersion.In terms of structural regulation,the research on the composition,structure evolution,scale,morphology and dispersion of core-shell nanomaterials has been carried out in recent years.In the preparation methods,self-assembly method,the sol-gel method,microemulsion polymerization,hard and soft template method and other technical means have different advantages and disadvantages for improving the thermodynamic stability and interfacial interaction of core-shell particles.In the matter of tribological mechanism,a large number of studies have revealed the dynamic evolution laws of core-shell particles in the process of friction.The tribological mechanism of core-shell nanoparticles has been clarified from multiple perspectives through the film lubrication mechanism,the permeable layer concept,the third body anti-wear mechanism,the rolling-bearing action and the self-consumption mechanism.In the application of lubricating materials,various functional core-shell nanoparticles play an important role in improving the properties of lubricant functional additives,polymer coa- tings and polymer composites.The results show that the core-shell nanoparticles with characteristic structural advantages are of great significance for improving the tribological properties and bearing capacity of lubricating materials. Based on the current research situation at home and abroad,this paper systematically reviews the common types,preparation methods,structure regulation mechanism,friction and wear mechanism of the core-shell composites,as well as the application in lubricating materials.The future research direction of core-shell nanomaterials in the lubrication and the failure mechanism,accurate compounding and performance optimization,and the self-healing mechanism of core-shell structure is also outlooked.