粘结固体润滑涂层中原位合成纳米粒子以提高涂层摩擦学性能的研究

Bonded solid lubricant coatings are widely used in many high technology fields to solve tribological problems, such as wear, lubrication, adhesion and scuffing of mechanisms encountering extreme environments and severe operating conditions, which would increase the stability and dependability of the mechanisms. Among the components of lubricant coating, nanofillers have a great importance to the tribological properties of lubricant coating. In order to improve the stability and homogeneity of the nanoparticles dispersed in lubricant coating, and to the bonding strength between the nanoparticles and lubricant coating, the organic or inorganic precursors containing elements of the target nanoparticles are dispersed uniformly into the lubricant coating. At high curing temperature, the precursor will be decomposed, and uniform stable nanoparticles can be synthesized in situ. Such nanoparticles would be bonded to the active functional groups of the binders chemically because of its high surface activity. The binding force could be increased and the intensity and properties of the lubricant coating could be increased meanwhile. The design, preparation and tribological properties of the lubricant coating filled with nanoparticles synthesized in situ will be studied, the effect of in-situ synthesized nanoparticles and physical added nanoparticles on the mechanical and tribological properties of the lubricant coating will be comparative investigated, and the internal relations and mechanism of action between the nanoparticles and lubricant coating will be explored. By the aforementioned researches, the basis of design and key technology of lubricant coating materials will be acquired.

固体润滑涂层在高技术领域有着广泛的应用，对于解决在极端苛刻工况条件下的磨损和润滑问题、提高设备运行的稳定性和可靠性具有十分重要的意义。在粘结固体润滑涂层的各组分中，纳米填料对涂层性能的影响至关重要。为了提高纳米粒子在涂层中的均匀分散稳定性及其与涂层树脂间的结合强度，本项目提出在涂层中均匀分散含有目标纳米粒子元素的有机或无机前驱体，在涂层加热固化的过程中前驱体受热分解，原位合成纳米粒子。利用新生成纳米粒子较高的表面活性，使之和粘结剂树脂中的活性官能团形成较强的化学键合，提高纳米粒子与粘结剂树脂间的结合力，从而提高涂层的强度和性能。本项目将开展原位合成纳米粒子填充涂层的设计、制备和摩擦学性能研究，对比考察原位合成纳米粒子和物理添加纳米粒子对涂层机械和摩擦学性能的影响，探究原位合成纳米粒子与涂层之间相互影响的内在联系及作用机理，形成具有优异摩擦磨损性能的固体润滑涂层材料的关键制备技术。

本项目开展了原位合成纳米粒子填充涂层的设计、制备和摩擦学性能研究，对比考察原位合成纳米粒子和物理添加纳米粒子对涂层机械和摩擦学性能的影响，探究了原位合成纳米粒子与涂层之间相互影响的内在联系及作用机理，主要研究内容包括：1. 以N, N-二乙基二硫代氨基甲酸银作为单源前驱体，通过其一步热分解在涂层中原位合成了尺寸小且分布均匀的Ag2S纳米粒子。涂层的固化温度不会影响Ag2S纳米粒子的尺寸、形貌和尺寸分布。原位合成Ag2S纳米粒子的添加，尤其是当其含量为5.0 wt.%时，极大增强了粘结固体润滑涂层的显微硬度和耐磨损性能，其增强效果要优于机械混合的Ag2S颗粒，但对涂层摩擦系数影响不大。2. 通过调节单源前驱体分子中取代烷基链长度和单源前驱体含量有效调控原位合成Ag2S纳米粒子的尺寸和尺寸分布。取代烷基链的变化使得原位合成的Ag2S纳米粒子表现出双峰和多峰尺寸分布。单源前驱体含量增多，Ag2S纳米粒子尺寸相应增大。原位合成Ag2S纳米粒子对涂层机械和摩擦学性能的增强不仅依赖于其分散性，还依赖于尺寸和尺寸均一性。具有均匀分散性、较小尺寸和双峰尺寸分布的Ag2S纳米粒子能更有效地改善涂层的机械和摩擦学性能，其增强效果归因于涂层承载能力的提高和均匀稳定转移膜的形成。3. 围绕纳米粒子/聚合物基质界面相互作用关系这一关键科学问题，设计了对比实验，通过“液相辅助”合成了Ag2S纳米粒子。获得的超小Ag2S纳米粒子分散非常均匀，粒径为1.0-2.0 nm。聚合物的存在极大限制了Ag2S纳米粒子的尺寸，但不会影响Ag2S纳米粒子的结晶性。此外，聚合物则通过PAI分子中的COOH与Ag2S纳米粒子中的Ag离子发生的配位化学反应，化学吸附到了Ag2S纳米粒子表面，这极大增强了Ag2S纳米粒子与聚合物基质间的相互作用。通过上述研究，形成了具有优异摩擦磨损性能的粘结固体润滑涂层材料的关键制备技术，并发展出了几种良好摩擦学性能的涂层材料，为解决我国对高性能润滑涂层材料的需求奠定了重要的基础。