Reactive-templated grain growth processing for lead free piezoelectric ceramics

Texture engineering using reactive-templated grain growth (RTGG) is reviewed as a key processing technique for lead free piezoelectric ceramics. Bismuth layer structured ferroelectric ABi(4)Ti(4)O(15) (A=Na0.5Bi0.5, Ca, Sr) ceramics with a highly preferred {001} orientation were fabricated with enhanced piezoelectric properties using Bi4Ti3O12 platelets. Textured simple perovskite type ceramics were also prepared in Bi0.5Na0.5TiO3 (BNT), BaTiO3 and K0.5Na0.5NbO3 (KNN) based compositions with Lotgering's factor higher than 0(.)8. The textured BNT and KNN based ceramics exhibited enhanced electromechanical coupling coefficients and piezoelectric constants when compared with their randomly oriented counterparts. The development of microstructure and texture in the RTGG processed ceramics is dependent on the target system, starting materials and processing parameters, and optimum preparation conditions must be found by analytical investigation.