科研之友
微信
新浪微博
Facebook
分享链接
摘要
Using solid lubricant coating is one of the effective methods to reduce the friction and wear of mechanical system. Waterborne polyurethane (WPU) has excellent mechanical properties, high flexibility and strong adhesion to the substrate. However, with the increasingly stringent requirements, the pure WPU coating system has not been able to provide ideal performance indicators, and it is necessary to introduce micron or nano materials to further improve the mechanical properties and tribological properties of waterborne polyurethane coating. In this study, the introduction of polytetrafluoroethylene (PTFE) microparticles and 2D black phosphorus (BP) nanoparticles modified waterborne polyurethane coating, BP/PTFE/WPU nanocomposite coatings were prepared by a simple spraying method. The morphology and structure of BP were characterized and analyzed by X-ray diffraction analyzer, laser confocal Raman spectrometer and atomic force microscope. The microstructure of the coating was observed by scanning electron microscope, and the elements and components were analyzed by EDS. According to GB/T 6739-2006, the pencil hardness of coating was tested by QHQ-A paint film pencil hardness tester. The adhesion of the coating was tested according to GB/T 9286-1998. The tribological properties of the coating were tested by UMT friction and wear tester. The wear surface was characterized by RTEC 3D profilometer and scanning electron microscope. The results showed that the bearing capacity of pure WPU coating was very poor. When the load exceeded 1 N, the wear life of the coating was less than 10 s, and the wear surface of the coating was seriously damaged, obvious microcracks appeared on the wear surface, and serious fatigue wear occurred on the wear surface. The introduction of PTFE improved the mechanical and tribological properties of the coating to some extent. When the solid content ratio of PTFE/WPU was 1:4, PTFE and WPU in the composite coating were fully combined, and the composite coating had excellent lubrication performance and adhesion performance. Under 8 N load, compared with the pure WPU coating, the wear of the coating surface after friction was improved, the wear width decreased from 693 μm to 497 μm, and the wear depth decreased from 30.6 μm to 10.2 μm. The friction coefficient and wear rate of PTFE/WPU composite coating were as low as 0.143 and 2.56× 10?4 mm3/(N·m), respectively. However, cracks and pores appeared on the coating surface after PTFE filled, which resulted in larger fluctuation of the profile curve of wear marks, which greatly affected the tribological properties of the composite coating. The further introduction of BP could fill and repair the surface defects of the coating and greatly enhanced the mechanical properties and tribological properties of the coating. The wear marks of BP/PTFE/WPU composite coating were very regular in 3D morphology. The inside of the wear marks was flat and smooth, and no scratches or groove was observed. The wear width and wear depth were reduced to 472 μm and 6.4 μm, respectively. When the mass fraction of BP was 1%, the BP/PTFE/WPU composite coating had the best tribological properties, and the friction coefficient and wear rate were further reduced to 0.085 and 5.73×10?5 mm3/(N·m) under 8 N load. In addition, BP/PTFE/WPU composite coating improved the hardness of the pencil from 3B to 2H. The excellent mechanical properties and tribological properties of the BP/PTFE/WPU composite coating were attributed to the improvement of the microstructure and surface hardness of the coating by BP. In addition, it was easy to form a stable transfer film on the friction surface to avoid direct contact of the friction pair during the rubbing process of the composite coating. ? 2023 Science Press.
- 单位
