Reciprocating sliding wear evaluation of a polymeric/coating tribological system

Abstract

In a reciprocating tribotester, five polymeric materials were evaluated against various hard coatings deposited on a stainless steel substrate. These polymeric/coating systems were compared with the wear of a baseline phenolic impregnated polytetrafluoroethylene (PTFE)/polyester woven fabric composite against an uncoated stainless steel substrate. Water was used as the lubricant, which contained alumina (Al 2O 3) particulates to simulate a contaminated environment. The polymeric composites used were two polyimides, a polyamide-imide, a polybenzimidazole and an injection-moldable polyether ether ketone (PEEK). The processing techniques and the amounts of PTFE, carbon fiber, graphite and other additives to reduce friction and improve wear were the significant differences. The hard coatings were deposited on a precipitation hardened PH 13-8 Mo stainless steel by different techniques, such as electrospark alloying, thermal spraying, electroless chemical conversion and physical vapor deposition. The wear scar generated on the fabric was larger than the alternative polymeric materials. The polymeric composites that contained PTFE additives exhibited greater wear resistance than the composites that did not contain this additive. In general, the harder the coating, the more resistant it was to damage by the Al 2O 3 particulate contaminants, subsequently producing a smaller wear scar on the polymer specimen.