Dielectric and piezoelectric properties of porous lead-free 0.5Ba(Ca_0.8Zr_0.2)O₃-0.5(Ba_0.7Ca _0.3)TiO₃ ceramics

Yan Zhang, Mengying Xie, James Roscow, Chris Bowen

OAI: oai:purehost.bath.ac.uk:openaire_cris_publications/ddc74bd5-78f2-46b3-b8a4-6ff80609186a • DOI: https://doi.org/10.1016/j.materresbull.2018.08.031

Porous barium calcium zirconate titanate 0.5Ba(Ca_0.8Zr_0.2)O₃-0.5(Ba_0.7Ca_0.3)TiO₃ (BCZT) lead-free ferroelectric ceramics were fabricated via a burnt polymer spheres (BURPS) technique by introducing corn starch as the pore-forming agent. The effect of porosity on the microstructure, dielectric, and piezoelectric properties of the porous materials were investigated. An increase in porosity volume fraction from 10% to 25% resulted in an increase in the hydrostatic charge coefficient (d_h), which was 140 to 560% higher than that of the dense BCZT material. An increase in porosity fraction from 10% to 25% also lead to a decrease in relative permittivity that was 16.7% to 60.4% lower than the dense material. These two changes in properties provided a significant enhancement of the hydrostatic figure of merit (d_h∙g_h) for the porous ceramic; for example the d_h∙g_h of the 25 vol.% porous BCZT ceramic was 158 times more than the dense ceramic and demonstrates the potential of porous lead-free ferroelectrics for piezoelectric transducer devices. Reasons for the significant enhancement in piezoelectric performance of the porous ceramics are discussed.

dielectrics Lead-free ceramic Piezoelectrics porous /dk/atira/pure/subjectarea/asjc/2500/2500 name=General Materials Science /dk/atira/pure/subjectarea/asjc/3100/3104 name=Condensed Matter Physics /dk/atira/pure/subjectarea/asjc/2200/2211 name=Mechanics of Materials /dk/atira/pure/subjectarea/asjc/2200/2210 name=Mechanical Engineering