Effect of micrometer sized ceramic particles on the tribological properties of Polytetrafluoroethylene based composites. (16th July 2020)

• Record Type: Journal Article
• Authors: Wang, Anying; Lin, Bin; Zou, Hongbo; Wei, Chibin; Meng, Yaqi; Sui, Tianyi; Yan, Shuai
• Is Part Of: Surface topography. Volume 8:Number 3(2020:Jul./Sep.)
• Publication Date: 2020-07-16
• Subjects: polytetrafluoroethylene -- Si3N4 -- SiO2 -- wear resistance; Surfaces (Physics) -- Periodicals; Surfaces (Physics) -- Measurement -- Periodicals; 530.417
• DOI: 10.1088/2051-672X/aba485
• Languages: English
• ISSNs: 2051-672X

Abstract

Abstract: Polytetrafluoroethylene (PTFE) is a self-lubricating matrix material with low friction coefficient and corrosion resistance but high wear rate. Ceramic particle fillers could effectively improve the tribological properties of PTFE-based composites, reduce its wear rate. However, there has been much debate about anti-wear mechanisms for particle fillers, which mainly focus on wear resistance micro-mechanism and mechanochemistry approach. In this paper, four kinds of PTFE-based composites filled with micrometer-sized ceramic particles (SiC, Si3 N4, SiO2 and h-BN) were prepared and tested to explore their tribology properties using a pin-on-disk tribometer. The filler proportions ranged from 5 to 20 wt% in 5 wt% increments were added. The worn surfaces of the composites and transfer films attached on the steel disk were examined by Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) and 3D topographies. Ultralow wear was observed on the PTFE/SiO2 and PTFE/Si3 N4 composites in wear tests, which was attributed to tribochemistry. There were protection films formed on the worn surface, which hindered further transfer of the composites. Meanwhile, adhesion of the transfer film was enhanced by metal-chelate salts of perfluorinated carboxylic acids formed by tribo-chemical reactions. The wear rate of PTFE decreased by three orders of magnitude (from 6.25 * 10 −4 to 2.21 * 10 −7 mm 3 /(Nm)) after addition of 20 wt% SiO2 particles. No chemical reaction was observed on the worn surface of PTFE/SiC and PTFE/h-BN composites.