in textured polycrystalline non-ferroelectric piezoelectric materials, such as AlN and ZnO. The families of ceramics with perovskite, tungsten-bronze, and related structures exhibit piezoelectricity: Lead zirconate titanate ( with 0 ≤ x ≤ 1) – more commonly known as PZT, the most common piezoelectric ceramic in use today. Potassium niobate (KNbO3) Sodium tungstate (Na2WO3) Ba2NaNb5O5 Pb2KNb5O15 Zinc oxide (ZnO) – Wurtzite structure. While single crystals of ZnO are piezoelectric and pyroelectric, polycrystalline (ceramic) ZnO with randomly oriented grains exhibits neither piezoelectric nor pyroelectric effect. Not being ferroelectric, polycrystalline ZnO cannot be poled like barium titanate or PZT. Ceramics and polycrystalline thin films of ZnO may exhibit macroscopic piezoelectricity and pyroelectricity only if they are textured (grains are preferentially oriented), such that the piezoelectric and pyroelectric responses of all individual grains do not cancel. This is readily accomplished in polycrystalline thin films. Lead-free piezoceramics Sodium potassium niobate ((K,Na)NbO3). This material is also known as NKN or KNN. In 2004, a group of Japanese researchers led by Yasuyoshi Saito discovered a sodium potassium niobate composition with properties close to those of PZT, including a high TC. Certain compositions of this material have been shown to retain a high mechanical quality factor (Qm ≈ 900) with increasing vibration levels, whereas the mechanical quality factor of hard PZT degrades in such conditions. This fact makes NKN a promising replacement for high power resonance applications, such as piezoelectric transformers. Bismuth ferrite (BiFeO3) – a promising candidate for the replacement of lead-based ceramics. Sodium niobate (NaNbO3) Barium titanate (BaTiO3) – Barium titanate was the first piezoelectric ceramic discovered. Bismuth titanate (Bi4Ti3O12) Sodium bismuth titanate (NaBi(TiO3)2) The fabrication of lead-free piezoceramics pose multiple challenges, from an environmental standpoint and their ability to replicate the properties of their lead-based counterparts. By removing the lead component of the piezoceramic, the risk of toxicity to humans decreases, but the mining and extraction of the materials can be harmful to the environment. Analysis of the environmental profile of PZT versus sodium potassium niobate (NKN or KNN) shows that across the four indicators considered (primary energy consumption, toxicological footprint, eco-indicator 99, and input-output upstream greenhouse gas emissions), KNN is actually more harmful to the environment. Most of the concerns with KNN, specifically its Nb2O5 component, are in the early phase of its life cycle before it reaches manufacturers. Since the harmful impacts are focused on these early phases, some actions can be taken