Anomalous Thermal Expansion in Solid-Phase Synthesis of Piezoceramic Material Based on Solid Solutions of Potassium and Sodium Niobates
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Anomalous thermal expansion of the pressed mixture of initial reactants is observed in solid-phase synthesis of piezoceramic materials based on complex oxides with perovskite structure. Under certain conditions the magnitude of this expansion can be an indicator of the degree of completion of the solid-phase reactions. The thermal expansion of the pressed mixture of powders of potassium and sodium carbonates and niobium oxide in the synthesis of the complex oxide potassium niobate and sodium niobate KNN is analyzed. It is shown that the temperature and completeness of the synthesis reaction can be determined on the basis of this analysis. The obtained material was used to prepare samples of piezoceramic with density to 92% of the theoretical value and piezoelectric modulus d33 to 1.0 × 10–10 C/N.
Key wordspiezoceramic material solid-phase synthesis potassium and sodium niobates anomalous thermal expansion
Financial support for this work was provided by the Ministry of Education and Science of the Russian Federation as part of the special federal program ‘Research and development in high priority directions of development of the scientific-technological complex of Russia in 2014 – 2020’ under contract No. 14.577.21.0221 (September 29th, 2016) on the subject ‘Development of a technology for obtaining textured piezoceramic for fabricating components for monitoring and positioning setups based on perovskite-like oxide ferroelectrics’ (unique identifier PNIEPRFMEFI57716X0221) using equipment from the Center for Collective Use at Moscow Polytechnic University.
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