Adaptive Tribological Coatings
|Dates:||28 June 2017|
|Times:||14:00 - 15:00|
|What is it:||Seminar|
|Organiser:||Department of Materials|
|Speaker:||Professor Andrey A. Voevodin|
Tribological coatings, which can re-arrange their structure and chemistry in tribological contacts in response to changes in environmental humidity or temperature,
are of a practical importance for aerospace, tooling, automotive, and other applications. The conceptual approaches highlighted in this presentation include “chameleon”
coatings made of hard nano-crystalline carbide, nitride and oxide matrices with additions of nano-inclusions of soft metals (Ag, Au), amorphous (MoS2, carbon) phases,
and transition metals capable of forming lubricating ternary oxides for lubrication over broad humidly (ambient to space) and temperatures (from cryogenic to 1000 °C).
The stored materials are released from nanophase reservoirs, facilitating chemical and structural changes of mechanical interfaces to continuously reduce friction and
wear in harsh environments. Furthermore, coating compositions can be modified to guide tribofilm formations made of oxygen defected double oxides (e.g. Magnéli phases)
as well as ternary oxides, where interlayered metallic and ionic bonding along specific crystallographic orientations provides sliding friction reduction for adaptive lubrication
in the challenging mid-temperature regime of 500-700 °C. The nanocomposite “chameleon” structures can also be sandwiched between diffusion barrier nitride layers for
extended operations and temperature cycling capability. In addition, coating nanostructure texture and orientation control can provide an opportunity to add thermal
management functionalities, using thermal conductivity anisotropy and phase transitions in tribological contacts. Techniques for coating preparation, methods for in-situ
characterization and identification of self-adaptation mechanisms, as well as tribological performance of adaptive surfaces in harsh environments, are discussed in detail.
Professor Andrey A. Voevodin holds a Chair position in the Department of Materials Science and Engineering in The College of Engineering, University of North Texas.
Before joining UNT in the Fall of 2015, he was a Principal Research Scientist and Team Leader at the US Air Force Research Laboratory’s (AFRL) Materials and Manufacturing
Directorate, where he established and led tribological, thermal management, and nanoelectronic material research laboratories. Prof Voevodin’s expertise includes thin film
deposition, plasma processes, surface engineering, surface analysis, electrical, thermal, and mechanical interfaces. His current research areas are nanolayered, nanostructured,
and 2-dimensional materials for electron and phonon transport, hybrid and pulsed plasma deposition technologies, surface engineering and high temperature tribology.
Dr. Voevodin has over 300 technical publications, from which 220 are in peer-reviewed archived journals, one book, eight book chapters, 12 patents and inventions.
Dr. Voevodin is a Fellow of AVS Science and Technology Society and serves as 2017 Chair for the Advanced Surface Engineering Division of AVS.
Division of the AVS.
Professor Andrey A. Voevodin
Role: Professor and Chair, Department of Materials Science and Engineering
Organisation: University of North Texas, Denton, USA
Travel and Contact Information
B22, ICAM, Pariser Building