Pölzlberger, D. E., Hahn, R., Wojcik, T., Salvadores Farran, N., Ntemou, E., Primetzhofer, D., Gachot, C., & Riedl-Tragenreif, H. (2025, June 16). Exploration of solid self-lubrication mechanisms of B₂O₃ in TiB₂±z based thin films [Conference Presentation]. ÖGV Seminar 2025, Wien, Austria. http://hdl.handle.net/20.500.12708/216986
Solid lubricants; Self-lubrication; PVD; Transition metal diborides
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Abstract:
Transition metal borides (TMBs) represent a highly promising family of materials for functional coatings due to their exceptional mechanical properties. These include a high melting point, extreme hardness, and outstanding resistance to wear. TMBs exhibit unique self-lubricating properties by forming boron oxide layers, reducing friction. The prevalent temperature strongly influences the formation of boron oxide. However, the fundamental mechanisms of this tribo-reaction are still not fully understood, particularly for TMB-based thin film materials.
Therefore, a detailed knowledge of the oxidation behavior of physical vapor deposited TiB2 thin films is crucial for understanding their friction and wear properties. Tribological tests reveal that sputter deposited super-stoichiometric TiB3.5 exhibits a significantly lower friction coefficient (~0.25), roughly half compared to that of sub-stoichiometric TiB1.7, tested at 500 °C. This reduction is attributed to the higher oxidation rate of super-stoichiometric TiB3.5 and the presence of B-rich tissue phases at the column boundaries. The oxidation data are further correlated with tribological, XRD, XPS, and TEM analyses, offering novel insights into the lubrication mechanisms of boron oxide across a wide temperature range.
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Forschungsinfrastruktur:
Analytical Instrumentation Center Röntgenzentrum Universitäre Service-Einrichtung für Transmissionselektronenmikroskopie
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Forschungsschwerpunkte:
Materials Characterization: 20% Surfaces and Interfaces: 80%