The Influence of Magnetron Sputtering Conditions on the Structure of Zr–Pd Coatings

Technical Physics Letters - Using the method of DC magnetron sputtering, nonstructured amorphous metal coatings of Zr75Pd25 composition were obtained with an average deposition rate of 1.3 nm/s at...     

Experimental Simulation of a Diamond Betavoltaic Battery

Diamond single-crystal Schottky barrier mip-structures (metal–intrinsic diamond–p-doped diamond) with dimensions of 3 × 3 and 4.1 × 4.28 mm are fabricated on the basis of HTHP p-diamond and CVD i-diamond. The betavoltaic characteristics of the diamond structures are studied using a wide-aperture electron beam with an initial energy of 110 keV, partially scattered on the way to a converter by a 14-μm-thick aluminum layer and a 17-mm-thick air layer. The maximum generated power reached 2.18 mW (41 mW/cm²) with a conversion efficiency of 2–3%.     

Shape‐Dependent Interactions of Palladium Nanocrystals with Hydrogen

Elucidation of the nature of hydrogen interactions with palladium nanoparticles is expected to play an important role in the development of new catalysts and hydrogen‐storage nanomaterials. A facile scaled‐up synthesis of uniformly sized single‐crystalline palladium nanoparticles with various shapes, including regular nanocubes, nanocubes with protruded edges, rhombic dodecahedra, and branched nanoparticles, all stabilized with a mesoporous silica shell is developed. Interaction of hydrogen with these nanoparticles is studied by using temperature‐programmed desorption technique and by performing density functional theory modeling. It is found that due to favorable arrangement of Pd atoms on their surface, rhombic dodecahedral palladium nanoparticles enclosed by {110} planes release a larger volume of hydrogen and have a lower desorption energy than palladium nanocubes and branched nanoparticles. These results underline the important role of {110} surfaces in palladium nanoparticles in their interaction with hydrogen. This work provides insight into the mechanism of catalysis of hydrogenation/dehydrogenation reactions by palladium nanoparticles with different shapes.     

Structure and tribological properties of composite materials based on Al–Cu–Fe formed at high pressure

The use of high pressure (~8 GPa) in the formation of composite quasi-crystalline materials from powders made it possible to create practically poreless samples with a density close to the maximum known for this type of quasi-crystals. For samples with a nickel binder, sintered at a temperature of 550°C, a very low coefficient of friction was obtained, which retain its value during the testing.     

Synthesis and characterization of macrocomposites based on nickel-coated quasi-crystalline Al-Cu-Fe powder

Disperse composite materials consisting of quasi-crystalline Al-Cu-Fe particles covered by nickel nanolayers have been obtained using a dusty plasma trap coating technology. These powders were processed into macrocomposites by cold pressing with subsequent sintering in hydrogen. The macrocomposites were studied by the electron microscopy, electron-probe microanalysis, and X-ray diffraction techniques. It is established that sintering at ∼750°C yields a high-strength macrocomposite that is not fractured under tribological testing conditions. Despite the fact the samples sintered at 750°C contain about 50 wt % of β phase, their friction coefficient is close to that of Al-Cu-Fe quasi-crystals.     

Equirate magnetron sputtering of mosaic copper-graphite targets

Based on experimental data on sputtering of copper-graphite cathodes, we propose a mechanism of equirate sputtering of elements of mosaic targets prepared from materials the sputtering yields of which differ by almost an order of magnitude. The mechanism takes into account the occurrence of a height discontinuity between the mosaic elements at the initial stage of sputtering, the redistribution of ion fluxes between the elements, and the effects related to the mass transfer in plasma and the implantation of sputtered atoms into the mosaic elements of the different variety.