Evolution of textured microstructure of Li-doped (K,Na)NbO3 ceramics prepared by reactive templated grain growth

Abstract

(K0.45Na0.55)0.94Li0.06NbO3 (KNLN) ceramics with high texture degree (Lotgering factor f=94%) were prepared by reactive templated grain growth (RTGG) using plate-like NaNbO3 (NN) templates. XRD patterns and SEM micrographs of the samples fabricated at different stages of RTGG were investigated. The XRD results revealed that NN templates reacted with KNLN matrix particles to form a solid solution at the first stage of RTGG. Then the significant template growth could only start when the sample’s relative density was higher than 90%. SEM observations revealed that the templated grains showed cubic-like feature instead of plate-like feature of NN template particles finally. The process of texture development and mechanism of template growth were discussed in detail. The piezoelectric coefficient d33 and electromechanical coupling factor kt of textured ceramics were 70% and 80% higher than that of nontextured ceramics with the same composition, respectively.