Lead free (K,Na)NbO3-based piezoelectric ceramics and transducers

Recent advances in (K,Na)NbO3-based ferroelectrics is reviewed, with special emphasis on the (K,Na)NbO3-LiTaO3-LiSbO3 system. Processing issues are elaborated on. The importance of precursor purity, moisture sensitivity and oxygen content on the dielectric and piezoelectric properties will be shown. Properties of prototype transducers are given and it will be shown that high performance metrics reminiscent to PZT-4 based transducers can be reached. Origins of high piezoelectric activity in the (K0.5Na0.5Li0.04)(Nb0.86Ta0.04Sb0.06)O3 is discussed, where it will be shown that this particular composition has a polymorphic phase transition in the vicinity of room temperature, and does not exhibit a morphotropic phase boundary..