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.

No description available.

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.