Tribological characterization of PTFE composites for ball bearing applications

Polymer-based ball bearings have emerged as a replacement for metal-based bearings in certain applications. They have recently gained attention due to their low weight-to-strength ratio, self-lubrication properties, and noncorrosive nature. The purpose of this article is to present the use of polytetrafluoroethylene (PTFE) in ball-bearing applications. In this study, five types of PTFE composites were selected, and their detailed tribological characterizations were performed based on the testing parameters of a polymer ball bearing with a bore diameter of 20 mm. Tribological characterization was performed using a pin-on-disc, in which the pin was sliding against the steel counterpart. The test pin was subjected to 100 to 150 N loads with 25 N steps at 1000,1200 and 1500 RPM. Further, wear analysis of the composites was performed using SEM and AFM, and the transfer of the film on the counterpart was analyzed using an optical microscope. The findings revealed that the 25% carbon-filled, 40% bronze-filled, and 15% PEEK-filled PTFE composites were suitable for ball-bearing applications for the defined load and speed. Pure PTFE and 25% glass fiber-filled didn't yield favorable results owing to the high wear rate.