Material Characterization and Influence of Sliding Speed and Pressure on Friction and Wear Behavior of Self-Lubricating Bearing Materials for Hydropower Applications

• Nowadays, hydropower plants are forced to have more frequent power control and the self-lubricated bearings used in the applications are one of the most critical components affected by the continuously changing operating conditions. In this study, microstructure and composition of two commercially available bearing materials (Orkot TXM Marine and Thordon ThorPlas) used in hydropower turbines were studied. In addition, the influence of sliding speed and applied pressure on the friction and wear behavior of the materials was investigated systematically for dry sliding conditions. The bearing materials were characterized using X-ray microtomography, Nuclear Magnetic Resonance (NMR) spectroscopy and Inductively Coupled Plasma–Sector Field Mass Spectrometry (ICP-SFMS) techniques. Friction and wear tests were carried out with a polymer pin sliding against a stainless steel (SS2333) plate with a linear reciprocating motion. Test conditions were: room temperature, 9–28 MPa pressure and 10–40 mm/s sliding speed ranges. Surface analysis of the polymer pins and the wear tracks were performed by optical profilometry, Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) techniques. Test results show that, for both materials, the coefficient of friction (COF) is decreasing at higher pressures. Surface analysis reveals higher concentrations of solid lubricants in the transfer layers formed at higher pressures, explaining the decrease in COF. Furthermore, the specific wear rate coefficients are increasing at higher sliding speeds, especially at lower pressures. Results of this study demonstrate that, under dry sliding conditions, changes in sliding speed and pressure have a significant influence on the tribological behavior of these bearing materials.

Ämnesord

Engineering and Technology  (hsv)

Materials Engineering  (hsv)

Composite Science and Engineering  (hsv)

Teknik och teknologier  (hsv)

Materialteknik  (hsv)

Kompositmaterial och -teknik  (hsv)

Engineering and Technology  (hsv)

Mechanical Engineering  (hsv)

Tribology (Interacting Surfaces including Friction, Lubrication and Wear)  (hsv)

Teknik och teknologier  (hsv)

Maskinteknik  (hsv)

Tribologi (ytteknik omfattande friktion, nötning och smörjning)  (hsv)

Engineering and Technology  (hsv)

Chemical Engineering  (hsv)

Chemical Process Engineering  (hsv)

Teknik och teknologier  (hsv)

Kemiteknik  (hsv)

Kemiska processer  (hsv)

Engineering and Technology  (hsv)

Mechanical Engineering  (hsv)

Fluid Mechanics and Acoustics  (hsv)

Teknik och teknologier  (hsv)

Maskinteknik  (hsv)

Strömningsmekanik och akustik  (hsv)

Natural Sciences  (hsv)

Chemical Sciences  (hsv)

Physical Chemistry  (hsv)

Naturvetenskap  (hsv)

Kemi  (hsv)

Fysikalisk kemi  (hsv)

Machine Elements  (ltu)

Maskinelement  (ltu)

Chemical Technology  (ltu)

Kemisk teknologi  (ltu)

Strömningslära  (ltu)

Fluid Mechanics  (ltu)

Chemistry of Interfaces  (ltu)

Gränsytors kemi  (ltu)

Nyckelord

sliding wear

friction

oscillating motion

self-lubricating

polymer composites

solid lubricants

X-ray microtomography

hydropower