Stress- and Time-Dependent Formation of Self-Lubricating In Situ Carbon (SLIC) Films on Catalytically-Active Noble Alloys

Autor: Frank W. DelRio, Michael Chandross, Tomas F. Babuska, Thomas E. Beechem, John F. Curry, Michael T. Dugger, Morgan R. Jones, Nicolas Argibay, Anthony E. McDonald
Rok vydání: 2021
Předmět:
Zdroj: JOM. 73:3658-3667
ISSN: 1543-1851
1047-4838
DOI: 10.1007/s11837-021-04809-5
Popis: Low shear strength (30 MPa) organic films were grown in situ on Pt0.9Au0.1 surfaces via cyclic sliding contact in dry N2 with trace concentrations of ambient hydrocarbons. We present a systematic investigation of the stress- and time-dependent film formation. Steady-state friction coefficients were found to be as low as µ ~ 0.015 and inversely proportional to contact pressure, revealing non-Amontonian behavior. Above a Hertzian contact pressure of ~500 MPa, shear strength dropped, indicating an activated process. Raman spectroscopy identified non-uniformity in areal coverage and relative order with contact pressure. Regions of steady-state low-friction behavior exhibited spectra similar to DLC coatings. Atomic force microscopy was used to study the formation and growth of films at the nanoscale. Stress- and time-dependent measurements suggested a sublinear increase of film volume with time, and a transition from growth to wear at a Hertzian contact pressure of ~1.2 GPa.
Databáze: OpenAIRE