Papers by Keyword: Nanostructured Material

Abstract: The article deals with technologies of refining and inoculating casting alloys with the use of nanostructured diamond powder, as well as stimulation technique on molten metal including processing of the liquid alloy with nanosecond electromagnetic pulses. The developed method of cast iron inoculation allows to eliminate the flare and to increase the physical and mechanical properties of the castings through the grain refining and the decrease of chilling tendency during crystallization of the liquid alloy. Inoculating of aluminium alloys by high-melting particles of a nanostructured diamond powder leads to the grinding of structural constituents, including conditions for dispersing hardening intermetallics during postbaking of such castings. As a result, foundry and physicomechanical properties of castings are significantly improved.

Abstract: A new concept for synthesis of the nanostructured transition metal oxides had been proposed. In particular, the method of pulsed high-voltage discharge was adopted for synthesis of α-MoO₃ nanostructure with orthorhombic crystal lattice. The as-prepared α-MoO₃ was investigated as anode for Li-ion battery. The 30-fold charge–discharge cycling has shown that material specific capacity (approximately 90 mAh g^–1) is not high, however excellent reversibility was achieved (the Coulombic efficiency equals to 99.9%). Thus the method opens new ways for the synthesis of nanomaterials with stable reversible capacities for Li-ion batteries.

Abstract: Ethanol sensing performance of gas sensors made of Fe doped and Fe implanted nanostructured WO₃ thin films prepared by a thermal evaporation technique was investigated. Three different types of nanostructured thin films, namely, pure WO₃ thin films, iron-doped WO₃ thin films by co-evaporation and Fe-implanted WO₃ thin films have been synthesized. All the thin films have a film thickness of 300 nm. The physical, chemical and electronic properties of these films have been optimized by annealing heat treatment at 300oC and 400oC for 2 hours in air. Various analytical techniques were employed to characterize these films. Atomic Force Microscopy and Transmission Electron Microscopy revealed a very small grain size of the order 5-10 nm in as-deposited WO₃ films, and annealing at 300oC or 400oC did not result in any significant change in grain size. This study has demonstrated enhanced sensing properties of WO₃ thin film sensors towards ethanol at lower operating temperature, which was achieved by optimizing the physical, chemical and electronic properties of the WO₃ film through Fe doping and annealing.