Now showing 1 - 3 of 3
  • Publication
    High temperature spark plasma sintering, a fast and one step route to achieve dense and efficient SrTiO 3 -based thermoelectric ceramics
    ( 2022) ;
    Moitrier, Florence
    ;
    Bourré, Thierry
    ;
    Delorme, Fabian
    ;
    Zaghrioui, Mustapha
    ;
    Giovannelli, Fabien
    Sr0.95La0.05)0.95 0.05TiO3 ceramics were prepared by solid state reaction and sintered by spark plasma sintering at different temperatures ranging from 1473 to 1873 K for 10 min. The thermoelectric properties show that sintering at temperatures higher than 1773 K allows reaching high thermoelectric properties similar to the ones obtained after annealing at high temperatures in H2/N2 for several hours. The high temperature sintered samples exhibit highest power factor near room temperature, resulting in ZT values higher than 0.1. Therefore, the 10 min short SPS process at high temperatures described in this paper is an easy, cheap, fast, and one step route to obtain dense and efficient SrTiO3-based thermoelectric ceramics. However, SEM observations show that the samples are not pure perovskite phase but contain titanium oxide and lanthanum compound aggregates.
      35  9
  • Publication
    Investigation of the electrocaloric effect in BaTiO3 multilayers by pASC calorimetry
    ( 2021) ;
    Sahraoui, Abdelhak Hadj
    ;
    Glorieux, Christ
    ;
    Leys, Jan
    ;
    Thoen, Jan
    ;
    Longuemart, Stéphane
    The electrocaloric heat production in BaTiO3-based multilayer ceramic capacitors with Y5V specification was measured in a direct way by means of an adiabatic calorimeter setup. Applying an electric field of 30 MVm−1 is found to result in a heat release of 0.94 Jg−1 and an electrocaloric temperature change of 0.46 K, in good agreement with direct results in previous studies.
      26  2
  • Publication
    Ultra-low thermal conductivity in scheelite and A-deficient scheelite ceramics
    ( 2021) ;
    Fabian Delorme
    ;
    Isabelle Monot-Laffez
    ;
    Fabien Giovannelli
    Synthesis of scheelite-type oxides based on lanthanum and barium molybdate (BaMoO and LaMoO ceramics) were successfully prepared via conventional solid-state reaction method. Dense ceramics were obtained by conventional sintering. Structural, microstructural and thermal properties of both sintered ceramics were assessed to identify the impact of cation deficiency on thermal conductivity. BaMoO ceramic has shown a decrease in thermal conductivity from 0.8 W m K to 0.65 W m K from 400 K to 650 K. The deficient scheelite LaMoO compound was found to further reduce thermal conductivity. An ultra-low thermal conductivity constant value of about 0.59-0.62 W m K was calculated over the entire temperature range. This value is the lowest recorded value for oxides so far discovered and such materials may be promising ones for thermal insulating applications.
      16  2Scopus© Citations 2