About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
High-Entropy Materials: Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond VI
|
| Presentation Title |
Mechanocatalysis on NiCoCr alloy: An in-situ atomic force microscopy study of stress-induced tribofilm formation |
| Author(s) |
Bunty Tomar, Vikas Paduri, Ritesh Sachan, Pranjal Nautiyal |
| On-Site Speaker (Planned) |
Bunty Tomar |
| Abstract Scope |
Catalytic alloys reduce wear at sliding contacts by forming carbon-based tribofilms from ambient hydrocarbons. These reactions are activated by mechanical stresses. This study explores the catalytic properties of NiCoCr, a multi-principal element alloy, to form tribofilms at unlubricated sliding contacts. Using in-situ atomic force microscopy, we investigated tribofilm growth mechanisms at single asperity sliding contacts. The tribofilm yield increased exponentially with stress, consistent with stress-assisted reaction rate theory. Tribofilm growth was self-limiting, reaching saturation as catalytic sites were exhausted. At elevated stresses, mechanochemical wear countered catalytic tribofilm growth, with the final film thickness determined by the competition between the two processes. These tribofilms prevented the wear of alloy under stresses exceeding 10 GPa, demonstrating NiCoCr’s potential as a self-lubricating material. We hypothesize that NiCoCr’s mechanocatalytic activity arises from its high lattice distortion, which lowers the energy barrier for stress-driven transformation of adsorbed hydrocarbons into protective carbon tribofilms. |