Effects of Oxygen Partial Pressure and Substrate Temperature on the Structure and Morphology of Sc and Y Co-Doped ZrO2 Solid Electrolyte Thin Films Prepared via Pulsed Laser Deposition

Chemical Vapour Deposition of Scandia-Stabilised Zirconia Layers on Tubular Substrates at Low Temperatures

The paper presents results of investigation on synthesis of non-porous ZrO₂-Sc₂O₂ layers on tubular substrates by MOCVD (metalorganic chemical vapor deposition) method using Sc(tmhd)₃ (Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)scandium(III), 99%) and Zr(tmhd)₄ (Tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)zirconium)(IV), 99.9+%) as basic reactants. The molar content of Sc(tmhd)₃ in the gas mixture was as follows: 14, 28%. The synthesis temperature was in the range of 600–700 °C. The value of extended Gr_x/Re_x² expression (Gr-Grashof number, Re-Reynolds number and x-the distance from the gas inflow point) was less than 0.01. The layers were deposited under reduced pressure or close to atmospheric pressure. The layers obtained were tested using scanning electron microscope (SEM) with an energy dispersive X-ray spectroscope (EDS) microanalyzer, X-ray diffractometer and UV-Vis spectrophotometer. The layers deposited were non-porous, amorphous or nanocrystalline with controlled chemical composition. The layers synthesized at 700 °C were nanocrystalline. ZrO₂-Sc₂O₃ layers with 14 mol.% Sc₂O₃ content had a rhombohedral structure.

Electrophoretic Deposition and Characterization of the Doped BaCeO3 Barrier Layers on a Supporting Ce0.8Sm0.2O1.9 Solid-State Electrolyte

In this study, the technology of electrophoretic deposition (EPD) micrometer barrier layers based on a BaCe_0.8Sm_0.19Cu_0.1O₃ (BCSCuO) protonic conductor on dense carrying Ce_0.8Sm_0.2O_1.9 (SDC) solid-state electrolyte substrates is developed. Methods for creating conductive sublayers on non-conductive SDC substrates under EPD conditions, such as the synthesis of a conductive polypyrrole (PPy) layer and deposition of a layer of finely dispersed platinum from a suspension of its powder in isopropanol, are proposed. The kinetics of disaggregation, disperse composition, electrokinetic potential, and the effect of adding iodine to the BCSCuO suspension on these parameters as factors determining the preparation of stable suspensions and successful EPD processes are explored. Button cells based on a carrying SDC electrolyte of 550 μm in thickness with BCSCuO layers (8–35 μm) on the anode, cathode, and anode/cathode side, and Pt electrodes are electrochemically tested. It was found that the effect of blocking the electronic current in the SDC substrate under OCV conditions was maximal for the cells with barrier layers deposited on the anode side. The technology developed in this study can be used to fabricate solid oxide fuel cells with doped CeO₂ electrolyte membranes characterized by mixed ionic–electronic conductivity (MIEC) under reducing atmospheres.