An ultrasonic therapeutic transducers using lead-free Na0.5K0.5NbO3–CuNb2O6 ceramics

Effects of CuO Sintering Aids on Microstructure and Electric Properties for (Na0.48K0.473Li0.04Sr0.007) (Nb0.883Ta0.05Sb0.06Ti0.007)O3 Ceramics

“…The piezoelectric effect has been widely used in various piezoelectric components, such as surface acoustic wave (SAW) filters, sensors, actuators, ultrasonic motors, transducers, speakers and energy harvesting. The National Bureau of Standards (NBS) reported the lead zirconate titanate PbTiO 3 -PbZrO 3 (PZT) as lead-based piezoelectric ceramics system in 1955 [1][2][3][4]. Because of the excellent piezoelectric behavior such as high surface phase velocity and electromechanical coupling coefficient, the PZT ceramics become the mainstream materials.…”

“…Because of the excellent piezoelectric behavior such as high surface phase velocity and electromechanical coupling coefficient, the PZT ceramics become the mainstream materials. However, there are a general awareness about environmental protection in recent year because of the Pb-based polluted materials [2][3][4][5]. European Union enforced the Restriction of the use of Hazardous Substance (RoHS) to restrict the heavy metal elements and their chemical compounds (Pb, Cd, Hg and so on) used at electrical and electronic engineering yields in 2006 [4].…”

“…In addition, the mainstream of lead-free piezoelectric materials includes (Bi 1−x Na x )TiO 3 (BNT) and (Na 1−x K x )NbO 3 (NKN) based materials. Although BNT materials have high tetragonal-cubic phase transition temperature (T C ~600 • C) and high mechanical quality factor (Q m ~7000), the electromechanical coupling coefficient k p is very low (~22%) and the bismuth element is also poisonous [2]. Therefore, the NKN material is one of the most potential candidate material system.…”

“…Therefore, the NKN material is one of the most potential candidate material system. The pure NKN materials have high piezoelectric coefficient and high phase transition (T C ~420 • C) [2][3][4][5][6]. However, since the Na and K atoms are volatile at the high sinter temperature (>800 • C), it is difficult to obtain the high density (4.25 g/cm 3 ) and high electromechanical coupling factor (k p = 25~35%) NKN-based ceramics by using traditional sintering process [2][3][4][5][6].…”

Phases, Microstructure, Dielectric and Piezoelectric Properties of Solid Solutions of the NaNbO3 System - CuNb2O6 Prepared From Nb2O5 of Various Qualifications

“…Their demand is determined by the possibility of solid solutions formation, TR, in a wide range of concentrations of components, the existence of morphotropic regions, MO, with the implementation in their neighborhood of practically important ferroelectric, FE, properties that differ markedly in each of the systems, which determines the diversity of areas of their possible applications [3]. The results of studies of some ternary systems and more complex compositions based on sodium niobate with the participation of ANb2O6 compounds [4] showed that copper-containing solid solutions were studied the least, although recently they have been the subject of close attention of researchers [5] who synthesized ternary systems using NaNbO3, KNbO3, CuNb2O6, which demonstrate very high mechanical and piezodielectric characteristics [6,[7][8][9] (Table 1). Considering this, as well as the well-known fact of the critical dependence of niobate materials on the physicochemical state of the main raw material component involved in the synthesis of TP, niobium pentoxide, Nb2O5, [10][11][12][13][14], we studied the synthesis and sintering of CuNb2O6 and one from the TP of the system (1-x) NaNbO3 -xCu0.5NbO3 (the formula of the copper-containing component is reduced to the perovskite form).…”