Texture‐Engineered Anisotropy in Piezoelectric and Ferroelectric Properties of Bismuth Titanate‐Ferrite (Bi ₅ Ti ₃ FeO ₁₅ ) Ceramics via Spark Plasma Sintering

ABSTRACT Bismuth titanate‐ferrite (Bi 5 Ti 3 FeO 15 ), as a promising high‐temperature piezoelectric ceramic, has disadvantages such as its poor piezoelectric constant ( d 33 = 7.1 pC/N) and low electrical resistivity at high temperature, which limit its practical applications in high‐temperature environments, in spite of its high Curie temperature ( T C = 761°C). In this study, we have prepared textured Bi 5 Ti 3 FeO 15 ceramics with up to 87.8% Lotgering factor ( f ) using a two‐step spark plasma sintering (SPS) technique. The textured Bi 5 Ti 3 FeO 15 ceramics exhibit superior piezoelectric properties, achieving a d 33 value of 29.7 pC/N, a fourfold increase over non‐textured counterparts. While maintaining a high T C of 772°C, these ceramics also demonstrate significant high‐temperature direct–current electrical resistivity ( ρ = 3.21×10 5 Ω cm at 500°C). These findings overcome the traditional drawbacks of Bi 5 Ti 3 FeO 15 , specifically its modest piezoelectricity and resistivity. The resulting textured ceramics, prepared through two‐step spark plasma sintering, exhibit the necessary properties for high‐performance use in high‐temperature piezoelectric devices.