| AVS 65th International Symposium & Exhibition | |
| Advanced Surface Engineering Division | Monday Sessions |
| Session SE+NS+TF-MoM |
| Session: | Nanostructured Thin Films and Coatings |
| Presenter: | Hanna Kindlund, Department of Mechanical and Aerospace Engineering, University of California Los Angeles (UCLA) |
| Correspondent: | Click to Email |
Transition-metal nitrides are refractory ceramics with high hardness, excellent wear resistance, high temperature stability, and good chemical inertness. Therefore, they are attractive in many applications, especially, as protective coatings against scratches, erosion, corrosion, and wear.
Tremendous efforts have been dedicated in enhancing hardness of ceramic films. However, in addition to high hardness, most applications also require high ductility, to avoid brittle failure due to cracking when coatings are subjected to high thermo-mechanical stresses. However, transition-metal nitrides, as most ceramics, are usually brittle, exhibiting low ductility and hence poor toughness.
Enhancing toughness in ceramic films is a challenging task that requires a fundamental understanding of the mechanical behavior of materials, which depends on their microstructure, electronic structure, and bonding nature. Theoretical studies using ab initio calculations predicted that alloys of VN with WN or MoN exhibit enhanced toughness as a result of their high valence electron concentrations, leading to an orbital overlap which favors ductility during shearing.
Here, I present experimental results on the growth of V1-xWxNy and V1-xMoxNy alloy thin films, their microstructure, mechanical properties and electronic structure, and relate these properties with their enhanced ductility, demonstrating that it is possible to develop hard-yet-ductile ceramic coatings.