Lead-based piezoceramic, such as lead zirconate titanate (PZT), is widely used because it has excellent piezoelectric properties near the morphotropic phase boundary (MPB). However, because of environmental issues associated with lead, the development of lead-free piezoceramics has attracted much attention recently. Solid solution of (K,Na)NbO3 (KNN), (K,Na)TaO3 (KNT) and LiNbO_3 (LN) is one of the leading candidates. An MPB was formed at composition [(K_(0.5)Na_(0.5))0.97~(Li)0.03](Nb_(0.8)Ta_(0.2))O_3(KNN-KNT-L0.03~N). Its piezoelectric response has been shown to be comparable to that of PZT system. However, complex texturing process is required to achieve the desired property. In this project, we investigated the KNN-KNT-LN system using conventional solid state reaction. The effects of increasing lithium, sintering process and the addition of CuO on the sample structure and electrical properties were studied. Remanent polarization of 28.39 μC/cm~2 was observed for the 0.1 wt% CuO added ceramic, which was sintered under pressureless condition.
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