Ultralow wear fluoropolymer composites : Nanoscale functionality from microscale fillers

• Polytetrafluoroethylene (PTFE) filled with certain alumina additives has wear rates over four orders of magnitude lower than unfilled PTFE. The mechanisms for this wear reduction have remained a mystery. In this work, we use a combination of techniques to show that porous, nanostructured alumina microfillers (not nanofillers) are critical for this wear reduction. The microscale alumina particles break during sliding into nanoscale fragments. X-ray microtomography, transmission electron microscopy and infrared spectroscopy reveal nanoscale alumina fragments accumulated in the tribofilms. Tribochemically generated carboxylate endgroups bond to metal species in the transfer film and to alumina fragments in the surface of the polymer composite. These mechanically reinforced tribofilms create robust sliding surfaces and lead to a dramatic reduction in wear. © 2015 The Authors. 

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Tribologi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Tribology (hsv//eng)

Keyword

Aluminum oxide

Polytetrafluoroethylene

Tribochemistry

Ultralow wear

Alumina

Carboxylation

Fillers

High resolution transmission electron microscopy

Infrared spectroscopy

Nanotechnology

Transmission electron microscopy

Tribology

Alumina particles

Aluminum oxides

Fluoropolymer composites

Orders of magnitude

Polymer composite

Polytetrafluoroethylene (PTFE)

Tribo-chemistry

X ray microtomography

Polytetrafluoroethylenes

Publication and Content Type

ref (subject category)

art (subject category)