Influence of wet contact conditions on the multidirectional fretting behavior of Polyetheretherketone and composites.pdfVIP

Polymer 108 (2017) 462e475 Contents lists available at ScienceDirect Polymer journal homepage: /locate/polymer In?uence of wet contact conditions on the multidirectional fretting behavior of Polyetheretherketone and composites K.A. Laux a, H.-J. Sue a, *, M.M. Hossain b, T. Bremner c a Department of Mechanical Engineering, Texas AM University, College Station, TX, USA b Department of Mechanical Industrial Engineering, Texas AM University-Kingsville, Kingsville, TX, USA c Hoerbiger Corporation of America, Inc., Houston, TX, USA article info Article history: Received 3 August 2016 Received in revised form 11 November 2016 Accepted 21 November 2016 Available online 25 November 2016 Keywords: Wet contact Fretting Static friction Wear Polyetheretherketone abstract Polyetheretherketone (PEEK) polymers are increasingly used in tribological applications where fretting damage occurs. Fretting wear results from the repeated sticking and slipping of mutually loaded contacts. In this study, a custom built multi-axis tribometer is used to replicate fretting of ?lled and un?lled PEEK in a pin-on-?at con?guration in both dry and wet conditions. The performance of the PEEK based polymers is shown to depend on the shear stresses generated when adhesive contacts are broken during slip. Un?lled PEEK experiences frictional heating that leads to softening of the wear surface. The softened material can be easily sheared from the bulk and leads to cratering and fracture of the samples. The extent of damage depended strongly on MW. The buildup of heat is prevented when water lubrication is used and wear is also reduced. Lubricating ?llers such as PTFE and graphite lower the frictional forces and reduce the tractive shear stresses. Filled samples however were susceptible to softening from water that exacerbated fretting damage. The fretting performance appears strongly tied to the static friction response on the material. Static friction measurement along with FEA analysis was conducted to