Cold Sintering of Perovskite–Perovskite Particulate Composite Based on K0.5Na0.5NbO3 and BiFeO3

The cosintering of particulate composites often presents a challenge due to the conventionally high processing temperatures used. Inter-diffusion of species between two phases and their volatilization, formation of secondary phases, and cracking or delamination of ceramics are effects that hinder the coupling of functional properties and reduce the final responses of such composites. This is particularly relevant when producing perovskite–perovskite composites from phases that are conventionally sintered at different temperatures (T s ), such as K 0.5 Na 0.5 NbO 3 (KNN; T s ≈1100 °C) and BiFeO 3 (BFO; T s ≈800 °C). Obtaining high-quality KNN–BFO multifunctional composite was the goal of this study. We demonstrate herein that the low-temperature sintering technique known as the Cold Sintering Process (CSP) can be utilized for producing particulate perovskite–perovskite composites, specifically KNN–BFO. We show that cold-sintered KNN–BFO composites have a dense microstructure, good phase-to-phase contact, are crack-free and exhibit ferroelectric properties. Their dielectric and ferroelectric properties are strongly affected by the fraction of KNN, increasing polarization saturation, while BFO aids in increasing their dielectric breakdown strength.