Novel synthetic approaches for YSZ and GDC ceramics and analytical characterization

Solid state ionics provide a fascinating interdisciplinary field of study since their discovery almost 200 years ago. Yttria-stabilized zirconia (YSZ) and gadolinium doped ceria (GDC) are the most technologically important compounds from this class of materials due to an excellent ionic conductivity. These materials can be used as oxygen-ion conducting membranes (solid electrolytes) in electrochemical devices. It is well known that physical properties of crystalline materials are dependent on the phase purity, grain size and grain size distribution. The aim of this study was to develop synthesis methods for the preparation of YSZ and GDC bulk ceramics and thin films investigating the effect of synthetic approach on the characteristics of the products. The additional aim was to develop an analytical methods for the determination of stoichiometry of ceramics and films. The effect of the synthesis method on the main characteristics of YSZ ceramics has been studied. YSZ ceramics have been prepared employing co-precipitation, sol-gel and sol-gel combustion methods. The sol-gel method have been successfully applied for the fabrication of YSZ thin films. GDC ceramics were successfully synthesized by sol-gel combustion and sol-gel processings. GDC thin films have been synthesized by chemical solution deposition using spin-coating technique. Spectrophotometric analytical approaches for the determination of chemical composition of all synthesized products have been proposed

YSZ ir GDC keraminių medžiagų sintezė šiuolaikiniais metodais ir analizinis apibūdinimas

Solid state ionics provide a fascinating interdisciplinary field of study since their discovery almost 200 years ago. Yttria-stabilized zirconia (YSZ) and gadolinium doped ceria (GDC) are the most technologically important compounds from this class of materials due to an excellent ionic conductivity. These materials can be used as oxygen-ion conducting membranes (solid electrolytes) in electrochemical devices. It is well known that physical properties of crystalline materials are dependent on the phase purity, grain size and grain size distribution. The aim of this study was to develop synthesis methods for the preparation of YSZ and GDC bulk ceramics and thin films investigating the effect of synthetic approach on the characteristics of the products. The additional aim was to develop an analytical methods for the determination of stoichiometry of ceramics and films. The effect of the synthesis method on the main characteristics of YSZ ceramics has been studied. YSZ ceramics have been prepared employing co-precipitation, sol-gel and sol-gel combustion methods. The sol-gel method have been successfully applied for the fabrication of YSZ thin films. GDC ceramics were successfully synthesized by sol-gel combustion and sol-gel processings. GDC thin films have been synthesized by chemical solution deposition using spin-coating technique. Spectrophotometric analytical approaches for the determination of chemical composition of all synthesized products have been proposed

Molten salt synthesis of micro-sized hexagonally shaped REMnO3 (RE = Y, Er, Tm, Yb)

Yttrium manganite (YMnO3) is a compound belonging to the hexagonal rare earth manganites family, which demonstrates multiferroic properties. This material can be prepared by several synthetic approaches, with the most common one being the solid-state synthesis. In this work, we show a possibility of preparing this material via molten salt synthesis using the NaCl-KCl mixture as the reaction medium and yttrium and manganese nitrates as the starting materials. We demonstrate that, by varying the reaction temperature and the nitrates-to-chlorides ratio, it is feasible to synthesize hexagonally shaped particles of microscopic dimensions. A similar synthesis procedure can be successfully applied for the preparation of other hexagonal manganites—ErMnO3, TmMnO3, and YbMnO3