Piezoelectric and Mechanical Properties of BaBi₄Ti₄O₁₅/Ba₄Ti₁₃O₃₀ Ceramics

This article presents the piezoelectric and mechanical properties of bismuth layer-structured ferroelectrics (BLSF)-based BaBi₄Ti₄O₁₅ ceramics incorporating Ba₄Ti₁₃O₃₀. The ceramic compositions, (1-x)BaBi₄Ti₄O₁₅–xBa₄Ti₁₃O₃₀ with x=0–100 vol%, are obtained through solid-state reaction processes. The dielectric constant, ε₃₃^T/ε₀, decreases exponentially from 220 to 97 with increasing x from 0 to 66 vol%. The electromechanical coupling factor, k₃₃, decreases from 15 to 7% with increasing x from 0 to 66 vol%. The fracture toughness, K_IC, and flexural strength, σ, of the compositions with x≥39 vol% are almost identical to those of Ba₄Ti₁₃O₃₀. At x≥39 vol%, K_IC and σ are nearly 15 and 30% larger than those of BaBi₄Ti₄O₁₅, respectively. Ba₄Ti₁₃O₃₀ particles dispersed uniformly in the ceramics are capable of carrying an applied load effectively and lead to further improvements of the mechanical properties.