Adaptive coatings are an important development in tribology. These coatings widen the range at which solid lubricants are useful in various environments. In this paper, coatings founded on molybdenum nitride are studied, with a focus on thermal cycling. These coatings were fabricated by unbalanced magnetron sputtering and characterized with techniques including x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, energy dispersive x-ray spectroscopy (EDS), and pin-on-disk tribometer. The results of two sets of coatings are reported. The first set of coatings is a nanocomposite of Mo2N/MoS2/Me (Me = Ag, Au, Cu). The second is a complex multi-layer system of Mo2N/Ag and a diffusion barrier of TiN which has been etched, then filled and coated with a layer of MoS2. After heating, these compounds produced silver molybdates. The Mo2N/MoS2/Ag nanocomposite shows promise with a 0.02 coefficient of friction at room temperature, while the multi-layer system eventually equilibrated at approximately 0.6. At high temperatures, again the nanocomposite was better, producing a 0.25 frictional coefficient compared to a 0.3 from the multilayer system. These results provide insight into what is needed to achieve thermal cycling.

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Double layer capacitors owe their large capacitance to high specific surface area carbon-based electrode materials adhered to a current collector via an adhesive. However, recent studies attribute greater electrical energy storage capacity to transition metal oxides/nitrides: a new generation of electrode materials for use in super-capacitors with mixed double-layer and pseudo-capacitive properties. Solution precursor plasma spray deposition is a technique that allows coatings to be fabricated with fine grain sizes, high porosity levels, and high surface area; characteristics ideal for application as super-capacitor electrodes. This investigation established conditions for deposition of porous, high specific surface area α-MoO3. It further identified a two-step temperature-programmed reaction for topotactic phase transformation of the α-MoO3 deposits into high specific surface area molybdenum nitrides of higher conductivity and higher electrochemical stability window. The electrochemical behavior of molybdenum oxide/nitride deposits was also studied in order to assess their potential for use in super-capacitors.

Double layer capacitors owe their large capacitance to high specific surface area carbon-based electrode materials adhered to a current collector via an adhesive. However, recent studies attribute greater electrical energy storage capacity to transition metal oxides/nitrides: a new generation of electrode materials for use in super-capacitors with mixed double-layer and pseudo-capacitive properties. Solution precursor plasma spray deposition is a technique that allows coatings to be fabricated with fine grain sizes, high porosity levels, and high surface area; characteristics ideal for application as super-capacitor electrodes. This investigation established conditions for deposition of porous, high specific surface area α-MoO3. It further identified a two-step temperature-programmed reaction for topotactic phase transformation of the α-MoO3 deposits into high specific surface area molybdenum nitrides of higher conductivity and higher electrochemical stability window. The electrochemical behavior of molybdenum oxide/nitride deposits was also studied in order to assess their potential for use in super-capacitors.

The aim of this thesis is to develop a tribocatalytically active solid coating that exhibits strong wear resistance, while also inducing the formation of carbon-based tribofilms when used in a hydrocarbon environment. By using tribocatalytic MoN-Cu synthesized through combinatorial DC reactive magnetron co-sputtering, a gradient between MoN and Cu is deposited and used to determine an ideal Cu composition exhibiting high wear resistance and the formation of a carbon-based tribofilm. To determine the properties of the thin film, various characterization methods were used before and after wear tests from an Anton-Paar pin-on-disk tribometer in a decane or ethanol bath. XRD, SEM, and EDS determined the phase structures and compositions. Nanoindentations and optical profilometry found hardness, Young's modulus, and wear rates. Raman analysis saw carbon presence on the surface of the wear tracks, confirming the formation of carbon tribofilms. For the wear rates, it was found that each fuel had different reactions to the changing Cu at%. From the Raman data, carbon presence, wear rates, and Cu at% did not reveal a strong correlation between the three sets of information. Specifically for the ethanol tracks, the was a connection between a high carbon amount and lower wear rate. It was inconclusive if there was one Cu at% that afforded the most ideal conditions. The information found here has developed the knowledge of MoN-Cu as a solid protective coating, and for using combinatorial DC reactive magnetron co-sputtering as an aid for materials development.