The effect of irradiated PTFE on the friction and wear behavior of chemically bonded PA46-PTFE-cb and PA66-PTFE-cb compounds

In this paper, various dry lubricants made of a polyamide (PA) matrix and two different grades of radiation-modified PTFE, which are chemically bonded to the matrix by reactive melt extrusion, are examined regarding their tribological suitability and compared to a PA-PTFE reference compound with non-modified PTFE. For this purpose, a block-on-ring test rig was used under ambient conditions, where the block made of dry lubricant is sliding on a steel ring made of 16MnCr5 with constant sliding speed. Results of tribological tests on the block-on-ring test rig such as wear and friction depending on the contact pressure are presented. In addition to that, analyses of the layer formation of the lubricants on steel counterparts are shown. An essential finding of the investigations is that the mass thickness on the tribologically stressed surfaces to be lubricated with the dry lubricant is not directly related to the compound wear, but rather depends on the pressure in the steel-compound contact. Furthermore, examinations showed that an increase of pressure in the block-ring contact does not lead to an increase of the amount of dry lubricant material on the steel surface.