Phase transition and electrical properties of lead free (Na0.5K0.5)NbO3–BiAlO3 ceramics

Crystal Structure and electrical properties of complex perovskite solid solutions based on (1-x) NaNbO3-xBi (Zn0.5Ti0.5) O3

“…Therefore, many systems have been extensively studied e.g. BaTiO 3 -based ceramics [3], Bi 0.5 Na 0.5 TiO 3 -based materials [4,5], Bi-layered structure materials [6] and alkaline niobate-based materials [7][8][9].…”

“…Pure NaNbO 3 is one of the more complex perovskite materials that possesses six successive phase transitions from paraelectric cubic phase at high temperature (>640°C) to antiferroelectric orthorhombic phase (Pbma or Pbcm) at room temperature (−100 to 360°C) and a ferroelectric phase at low temperatures (<−100°C) [12,13]. Also, NaNbO 3 can be an end member in many solid solutions including compounds such as (K 0.44 Na 0.52 Li 0.04 )(Nb 0.86 Ta 0.10 Sb 0.04 )O 3 [7] and Na 0.5 K 0.5 NbO 3 [7,8] which possess comparable ferroelectric and piezoelectric properties to that of PZT.…”

The variation of Curie temperature and dielectric relaxor behaviour in the nominal (1-x)BaTiO3-xBiAlO3 system

“…So it was expected that this method can be extended to the preparation of pure BiAlO 3 perovskie phase, meanwhile, the properties of both the host compound and BiAlO 3 could be modified. In this way, many solid solutions, such as BaTiO 3 -BiAlO 3 [7], (Na 0.5 Bi 0.5 )TiO 3 -BiAlO 3 [8], (Na 0.5 K 0.5 )NbO 3 -BiAlO 3 [9] and PbTiO 3 -BiAlO 3 [10], have been proposed. However, it should be noted that the Curie temperatures of these solid solutions strongly decrease with the increase of BiAlO 3 content, even lower than that of the host compound.…”

“…Although this law is often broken and the theoretical backing needs to be further clarified, in some instances, it serves as a useful rule and also can be extended to the more complicated system with multiplicity of phases, such as (1-x)PNN-xPZT [12], (1-x)PZN-xPZT [13] and (1-x) KNN-xLiNbO 3 [14]. So there aroused the suspicions that what is the main reason responsible for the large deviation of Curie temperature from Vegard's law in the reported BiAlO 3 based system [7][8][9][10]. It is believed that the Curie temperature reflects the stability of oxygen octahedron, which can be influenced by the occupation state of A or B ions in ABO 3 perovskite structure [15].…”

Dielectric, ferroelectrics properties and impedance spectroscopy analysis of the [(Na0.535K0.480)0.966Li0.058](Nb0.90Ta0.10)O3-based lead-free ceramics

“…2 However, their piezoelectric properties could be enhanced by introducing Li and Ta, respectively, into the A and B sites of perovskite-structured NKN ceramics. 5,[9][10][11][12] On the other hand, the [(Na 0:535 K 0:480 Þ 0:966 Li 0:058 ] (Nb 0:90 Ta 0:10 ÞO 3 (NKLNT) system has been paid considerable attention on account of the existence of a orthorhombic and tetragonal morphotropic phase boundary (MPB). 13 However, the major drawbacks of (Na,K)NbO 3 -based ceramics are (i) high hygroscopicity of the used precursors, (ii) the temperature instability due to the lower orthorhombictetragonal transition temperature (T oÀt ), and (iii) the difficulty to obtain fully dense ceramics due to the evaporation of potassium and sodium during the sintering process.…”