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(Pbcm) to FE(R3c), 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.