“…Table 4 presents the determined values of γ and δ. This enhancement in diffusion levels, especially near the morphotropic phase boundary (MPB), is likely attributed to disturbances at the A-site, involving Na + /Bi 3+ and Ca 2+ ions [ 18 , 57 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The electrical properties of NBT-based materials are enhanced principally through phase boundary engineering and optimization of the preparation procedure [ [15] , [16] , [17] ]. In specific, (1- x )NBT- x BT and (1- x )NBT- x CT systems materials have been regarded as one of the most promising lead-free ferroelectric compounds [ 18 , 19 ]. Subramani et al investigated the influences of tetragonal CaTiO 3 (CT) addition on the sintering, properties, microstructures, and characteristics of (Na 0.5 Bi 0.5 )TiO 3 (NBT) materials, and inferred that a little BT is advantageous for enhancing the dielectric performance of NBT materials [ 20 ].…”
“…Table 4 presents the determined values of γ and δ. This enhancement in diffusion levels, especially near the morphotropic phase boundary (MPB), is likely attributed to disturbances at the A-site, involving Na + /Bi 3+ and Ca 2+ ions [ 18 , 57 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The electrical properties of NBT-based materials are enhanced principally through phase boundary engineering and optimization of the preparation procedure [ [15] , [16] , [17] ]. In specific, (1- x )NBT- x BT and (1- x )NBT- x CT systems materials have been regarded as one of the most promising lead-free ferroelectric compounds [ 18 , 19 ]. Subramani et al investigated the influences of tetragonal CaTiO 3 (CT) addition on the sintering, properties, microstructures, and characteristics of (Na 0.5 Bi 0.5 )TiO 3 (NBT) materials, and inferred that a little BT is advantageous for enhancing the dielectric performance of NBT materials [ 20 ].…”
“…Lead-based ceramics are the most commonly utilized piezoelectric materials for piezoelectric sensors, actuators, and transducers on account of their excellent piezoelectric characteristics. , Considering the toxicity and volatility of lead oxides in materials, there is an increased demand for lead-free materials as well as biocompatible and environmentally friendly materials. , Recently, several lead-free piezoceramics have been produced; within them, perovskite lead-free solid solutions which are based on K 0.5 Na 0.5 NbO 3 (KNN), BaTiO 3 (BT), (Na 0.5 Bi 0.5 )TiO 3 (NBT), and (K 0.5 Bi 0.5 )TiO 3 (KBT) are very promising eco-friendly piezoceramics. − Nevertheless, these solid solutions need to be analyzed to be utilized in a commercial way. The principal challenge for BT-based piezoceramics is their comparatively lower curie temperature ( T c ), making the operating temperature range limited, whereas for KNN- and KBT-based piezoceramics, the difficulty lies in producing densely packed ceramics in a reliable manner. , Sodium bismuth titanate ((Na 0.5 Bi 0.5 )TiO 3 , abbreviated as NBT) , is a very well-known antiferroelectric material with a rhombohedral perovskite R 3 c structure.…”
Section: Introductionmentioning
confidence: 99%
“… 3 , 4 Recently, several lead-free piezoceramics have been produced; within them, perovskite lead-free solid solutions which are based on K 0.5 Na 0.5 NbO 3 (KNN), BaTiO 3 (BT), (Na 0.5 Bi 0.5 )TiO 3 (NBT), and (K 0.5 Bi 0.5 )TiO 3 (KBT) are very promising eco-friendly piezoceramics. 5 − 8 Nevertheless, these solid solutions need to be analyzed to be utilized in a commercial way. The principal challenge for BT-based piezoceramics is their comparatively lower curie temperature ( T c ), making the operating temperature range limited, whereas for KNN- and KBT-based piezoceramics, the difficulty lies in producing densely packed ceramics in a reliable manner.…”
Lead-free ceramic materials produced from bismuth sodium
titanate
(Na0.5Bi0.5TiO3, NBT)–bismuth
potassium titanate (K0.5Bi0.5TiO3, KBT) have been developed through a solid-state reaction technique.
The structural, dielectric, and piezoelectric characteristics of the
ceramic materials were analyzed. Based on the XRD investigation, the
morphotropic phase boundary (MPB) was determined for the composition
(x (%) = 16 and 20). The effects of the KBT phase
on the NBT lattice were examined using the charge density distribution.
Furthermore, the dielectric properties indicated the presence of a
negative dielectric constant (εr′) as a function
of frequency between 1 kHz and 2 MHz. Negative permittivity was observed
globally in the (1 – x)NBT–xKBT ceramic which reflects the effect of the dielectric
resonance. The grain conduction effect is revealed through the complex
impedance spectrum in the form of a semicircular arc within the Nyquist
plot. In addition, the samples studied revealed a non-Debye relaxation
phenomenon. The relaxation time was determined based on the Vogel-Fulcher
law for all samples. DC conductivity was carried out on the ceramics
material and revealed that the resistance decreases with increasing
temperature indicating a negative temperature coefficient of resistance.
The AC conductivity as a function of frequency for different temperatures
suggests the presence of a thermally activated conduction mechanism.
The activation energy has been determined based on the Arrhenius plot
of the DC electrical conductivity as well as the relaxation frequency.
“…Sodium bismuth titanate, (Na 0.5 Bi 0.5 TiO 3 ; (NBT), has been proposed as a potential candidate for lead-free piezoelectric ceramics based on its excellent ferroelectricity at ambient temperature. [1,2,3,4] Sodium bismuth titanate is characterised by having a rhombohedral perovskite structure with (a = 5,4884 Å and c = 13,5045 Å). [5,6] Relaxor ferroelectric materials represent a special class of disordered structures exhibiting a particular structure and properties.…”
1-x)(Na 0.5 Bi 0.5 )TiO 3-x BaTiO 3 , Rietveld refinement, Hydrothermal method, Nyquist impedance plot, Diffuse ferroelectric behaviour Sodium bismuth titanate (Na 0.5 Bi 0.5 )TiO 3 perovskite is presented as a lead-free concurrent for electro-ceramic engineering technologies. In this paper, (1-x)(Na 0.5 Bi 0.5 )TiO 3-x BaTiO 3 type ceramic materials were obtained by the hydrothermal process at a very low heat treatment temperature of around 200 °C and for times up to 24 hours. The structural, microstructural, and dielectric properties of the ceramic materials were investigated. The X-ray diffraction analysis confirms the formation of the rhombohedral phase of NBT with space group R3c. Based on the Rietveld refinement, the morphotropic phase boundary (MPB) was determined for the composition x (%) = 5 and 7. The grains increase in size from 11 to 23 µm and their distribution widens with an increasing barium concentration in the morphotropic phase boundary. The dielectric constants were measured from room temperature to 600 °C for various frequencies in the range of 1 kHz -2 MHz. From the Nyquist impedance plot, the effect of the grain and the grain boundaries on the electrical properties was studied. At high temperatures, the Uchino law modified by Echatoui et al. allows one to describe the thermal variation of the permittivity. This diffuse character is attributed to a cationic disorder due to the distribution of Na + /Bi 3+ and Ba 2+ ions in the A site.
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