Browsing by Author "V’yunov, O. I."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Lead-free high-temperature barium titanate- based PTCR ceramics and its electrical properties
    (Видавництво Львівської політехніки, 2012) Plutenko, T. A.; V’yunov, O. I.
    The (1-x)BaTiO3-x{Na,K}0.5Bi0.5TiO3 solid solutions have been synthesized by solid-state reaction technique. The parameters of the crystal structure of the ceramic samples were determined by means of Rietveld fullprofile X-ray analysis. With increasing x, the values of ρmax and ρmin increase due to the growth of potential barrier at grain boundaries. It has been found that in (1-x)BaTiO3 x{Na,K}0.5Bi0.5TiO3 system the grain boundary and the outer layer region make a contribution to the PTCR effect.
  • Thumbnail Image
    Item
    The structure and Ionic conductivity of Li0.5-yNayLa0.5 {Nb,Та}2O6 system
    (Видавництво Львівської політехніки, 2012) Kobylianska, S. D.; V’yunov, O. I.; Gavrilenko, O. N.; Belous, A. G.
    We have synthesized Li0.5–yNayLa0.5 Nb2O6 and Li0.5-yNayLa0.5 Ta2O6 defect perovskite solid solutions with 0 < y ≤ 0.5. Lithium ion diffusion in the investigated system exhibits no percolation effect. In the Li0.5-yNayLa0.5 Nb2O6 system, the ionic conductivity as a function of sodium content has a maximum due to two competing factors: the increase in perovskite cell volume and the decrease in lithium ion concentration. The ionic conductivity of Li0.5-yNayLa0.5 Ta2O6 samples decreases with sodium content.