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

Abstract

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 Grx/Rex2 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.

Recent Advances and Challenges in Thin-Film Fabrication Techniques for Low-Temperature Solid Oxide Fuel Cells

“…They reported that higher pressures resulted in lower gas flow and a thicker diffusion layer. Recently, Sawka [319] also synthesised ScSZ layers on tubular substrates using the MOCVD route in the temperature range of 600-700 • C using Zr(tmhd) 4 and Sc(tmhd) 3 by optimising the synthesis conditions including Grashof number (Gr), Reynolds number (Re), and distance from the gas flow input (x). The results showed a low value of about 0.01 for the extended Gr x /Re x 2 .…”

Structural, Morphological and Optical Properties of Nanostructured ZrO2 Films Obtained by an Electrochemical Process at Different Deposition Temperatures

“…A considerable number of research articles report ZrO 2 structures obtained by different methods, such as the following: sol-gel method [18], magnetron sputtering [19,20], chemical vapor deposition [21], electron beam physical vapor deposition (EBPVD) [22], laser ablation [23], hydrothermal method [24], and atomic layer deposition [25]. A key element in the design of zirconia nanostructures is the choice of technique and approach for their elaboration, which ensures the presence of needed properties and qualities, and predetermines specific applications.…”