Effect of Recovered Silicon Filler Inclusion on Mechanical and Tribological Properties of Polytetrafluoroethylene (PTFE) Composite

Polytetrafluoroethylene (PTFE) polymer-based tribo components are extensively used in various sliding applications such as PTFE seals, bearings, bearing cages, and surface coating for metal parts. The usage of industrial waste filler particles tailors the properties that aren’t sometimes exhibited by regular filler materials. This paper deals with the effect of recovered silicon fine wafer fillers varied from 1 to 5 wt% on tribo behaviour of PTFE matrix. Hot press sintering technique was used for the fabrication of PTFE/Silicon composites and characterized for chemical, mechanical, and tribo properties. Shore D hardness of the PTFE/5 wt% Silicon composite was increased to 45 % as compared to virgin PTFE polymer. When comparing with virgin PTFE polymer the friction coefficient and specific wear rate of the PTFE/5 wt% Silicon composite was decreased to 25 and 93 % respectively at maximum loading of 1.5 MPa. Silicon concentration beyond 3 % has not greatly improved the antifriction performance of PTFE/Silicon composite. In dry conditions, it was shown that the forming of a polymeric transfer film aided by silicon filler reduces the friction coefficient and specific wear rate. Scanning Electron Microscopy (SEM), Raman spectroscopy, and optical microscopy were used to investigate the worn surfaces and transfer film formation to understand the wear mechanism.