Susceptible Antiferroelectric/Ferroelectric Transitions in Silver Niobate-Based Ceramics Induced by Manual Mechanical Processing

It is common that the as-sintered bulk ceramics or powders undergo mechanical and/or heat treatment for further investigating the structure or properties. However, if their structures change during these procedures, it would mislead their structure-properties relation and subsequently lead to the wrong design of the desired ceramic products. In this work, we reported the mechanical/heat treatment effect on the structures of AgNbO₃-based antiferroelectric/ferroelectric (AFE/FE) materials. The results revealed that the structure of AgNbO₃-based systems with chemical compositions close to/in the AFE/FE phase boundary strongly depends on the history of polishing/grinding and/or annealing processing. Manual polishing/grinding (or milling) ceramic bulk/powders can induce a phase transition from AFE(<i>Pbcm</i>) to FE(<i>R</i>3<i>c</i>), and the transition can be reversed via the heat treatment, which is intimately related to a temperature-driven phase transformation having a metastable AFE phase. Our finding thus provides new insight into phase transitions in AgNbO₃-based systems, suggesting that the proper parameters of processing need to be considered to enable the development of an understanding of structure-property relationships in ceramic materials.