Nitride Discovery - Creating the Knowledge Base for Hard Coating Synthesis
The objective of this research program is to develop a systematic method to determine the intrinsic physical properties of transition metal nitrides. The project uses a combination of experiments and density functional calculations, to determine intrinsic elastic properties, hardness, and oxidation resistance values for binary nitrides. Stress-free single crystal layers of unexplored nitrides are deposited using ultra-high vacuum reactive sputter epitaxy. Intrinsic mechanical properties and high temperature oxidation rates are measured and directly correlated to results from first-principles calculations. This correlation is used to develop a complete property dataset for all binary transition metal nitrides, and this knowledge is used to develop a quantitative model that relates composition of ternary and off-stoichiometric nitrides to mechanical properties, using both measured and calculated electron density of states and the composition-dependent Fermi level, which determines charge transfer and bond directionality. This project is expected to provide the knowledge that has the potential to transform the multi-billion-dollar hard coating industry with a new coatings design approach.