High‐entropy materials, an exciting new class of structural materials involving five or more elements, are emerging as unexplored ground for superconductors. Here, the effects of nitrogen ...stoichiometry are investigated on local chemical structure of TiZrNbTa‐based thin films by various X‐ray‐based techniques. Lattice distortion and short‐range order of a set of TiZrNbTaNx samples, including bond lengths of different atomic pairs and coordination numbers of substituting atoms are quantitatively studied. The maximum superconducting transition temperature Tc is found at 10 K for a near‐stoichiometric (TiZrNbTa)N1.08 film, which is >8 K measured for a metallic TiZrNbTa film. The underlying electronic structure and chemical bonding in these high entropy nitrides thus influence the superconducting macroscopic properties.
High‐entropy materials are unexplored ground for superconductors. The effects of nitrogen stoichiometry on local structure, lattice distortion, and short‐range order of TiZrNbTa‐based thin films are investigated. The maximum superconducting transition temperature Tc is found at 10 K for a near‐stoichiometric (TiZrNbTa)N1.08 film. The underlying electronic structure and chemical bonding in these high entropy nitrides influence the superconducting macroscopic properties.
The performance of carbon nitride (CNx) coated roller bearings is investigated, using a micropitting rig. The rolling performance is evaluated using Stribeck test, with a continuously varying rolling ...speed (0.2 – 2m/s). Rolling contact fatigue tests with constant speeds (0.5, 1, 2, and 3.5m/s) are also conducted in order to study the high-cycle performance of the rollers. The obtained Stribeck curve shows that the presence of coatings eliminates run-in, resulting in low friction coefficients (∼0.08). Raman spectroscopy, performed at the wear tracks, reveals that CNx maintain stable chemical state. Coatings show abrasion although the wear rate is not detrimental for the performance of the rollers, since a CNx-to-steel contact is retained during the entire rolling contact fatigue test.
•CNx eliminates run-in effects in boundary and mixed lubrication.•Stribeck curve of CNx-coated rollers show no boundary lubrication.•CNx-rollers yield lower friction than uncoated under elastohydrodynamic lubrication.•CNx coated-rollers have improved wear-resistance in rolling contact fatigue tests.•CNx presence increase performance and lifetime of bearings.
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