Preparation and Structural Characterization of Complex Oxide Eutectic Precursors from Polymer–Salt Xerogels Obtained by Microwave-Assisted Drying

• Main Authors: Maria Vartanyan, Ilya Voytovich, Irina Gorbunova, Nikolay Makarov
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Materials
• Subjects: sol–gel process; polyvinyl alcohol; carboxymethylcellulose; polyvinylpyrrolidone; ternary oxide eutectics; microwave-assisted drying
• Online Access: https://www.mdpi.com/1996-1944/13/8/1808

Sol–gel synthesis is an acknowledged method for obtaining fine inorganic powders of a different nature. Implementation of water-soluble polymers as gel-forming media makes this technique even more readily available, especially in cases where conventional gel formation is suppressed. In polymer–salt solutions, polymers serve as scaffolds for salt constituents’ bulk crystallization. When dried, solid salt particles are deposited on the polymer surface or in polymer matrix pores, which leads to higher grain size uniformity. The present work discusses the effect of drying conditions on phase composition and structure characteristics of complex oxide eutectics in ternary systems, CaO–Al₂O₃–Y₂O₃ (CAY) and MgO–Al₂O₃–Y₂O₃ (MAY), obtained from polymer–salt compositions based on polyvinyl alcohol (PVA), Na-salt of carboxymethylcellulose (Na-CMC) or polyvinylpyrrolidone (PVP). Microwave-assisted drying proved to be more efficient compared to convective process; however such technique requires careful selection of gel-forming polymer.