Effect of Calcination Temperature on Dielectric Properties of CaCu3Ti4O12 Ceramics

Abstract

The effect of calcination temperature on the properties of CaCu 3 Ti 4 O 12 (CCTO) ceramics was studied. CCTO ceramics were prepared using solid state reaction method. The raw materials of CCTO were wet mixed for 24 hours and was dried overnight. CCTO powders were then calcined at three different temperature which is at 900 o C, 930 o C and 985 o C for 12 hours. The calcined powders were compacted at 250 MPa and then were sintered at 1040 o C for 10 hours. X-Ray Diffractometer (XRD) analysis showed the formation of CCTO phase and secondary phases of CuO for C900 calcined powder but single phase of CCTO was obtained by C930 and C985 calcined powders. Single phase of CCTO also were seen for all sintered samples. Observation on Scanning Electron Microscopy (SEM) micrographs showed abnormal grain growth or large grain size was seen in C900 sample and finer grain size was observed for C930 and C985 sintered samples. C900 sintered sample obtained the highest dielectric constant (10,462) and the lowest dielectric loss (0.061) measured at 1 MHz.

Trirelaxor Ferroelectric Material with Giant Dielectric Permittivity over a Wide Temperature Range

“…It should be noted that the strong dielectric response in the trirelaxor is comparable with that in another category of inorganic compound material CaCu 3 Ti 4 O 12 , which shows colossal permittivity over a wide temperature range, , and ε r can reach a value above 10 000 in a wide temperature window. Nevertheless, such a material system inherently exhibits a fairly high dielectric loss (10–300%) and a low breakdown field (1–8 kV/cm), which makes it difficult for such a material system to withstand a relatively high alternating electric field and thus far from being used for energy density storage and as an electrocaloric device. ,, In contrast, the trirelaxor ferroelectric material (BC 0.22 TS 0.12 ) shows a low loss tangent value (tan δ < 5%) in Figure a4 and a high breakdown strength (∼130 kV/cm) in Figure S2. Therefore, the trirelaxor ferroelectrics can be regarded as promising material systems for relevant practical applications.…”

“…Efforts have been made, and a common way of achieving a balanced permittivity–stability combination is to use a subclass of ferroelectrics, i.e., a relaxor, which is characterized by polar nanoregions (PNRs) contrasting with an ordinary macrodomain ferroelectric state. − Unlike normal ferroelectrics, it undergoes a relaxor transition, which is diffuse in nature and thus provides a broad permittivity peak across its relaxor transition region. , This enables better temperature stability as compared with that of normal ferroelectrics. However, the improved temperature stability is at the expense of reduced permittivity values relative to its ferroelectric counterpart, and this can be seen in Pb­(Mg 1/3 Nb 2/3 )­O 3 –PbTiO 3 , (Ba,Ca)­(Ti,Hf)­O 3 , and K 0.5 Na 0.5 NbO 3 –BaTiO 3 systems. ,, Another category of materials with colossal dielectric permittivity (e.g., CaCu 3 Ti 4 O 12 ) seems to have solved the permittivity–stability trade-off, but their inherent high dielectric loss and low breakdown field preclude them from being a candidate material for advanced energy storage and electrocaloric applications. , Therefore, there is still a lack of an effective approach to achieving giant permittivity materials with reasonable temperature stability considering the requirement of low loss and high breakdown voltage.…”

Effective dielectric loss (tan δ) reduction of CaCu3Ti4O12 (CCTO) via various addition of glasses

“…Several approaches have been used to reduce tan δ of CCTO through the application of different processing parameters, doping different elements into CCTO or combining it with another material to produce composite . One of the most interesting approaches is by fabrication of CCTO composites via incorporation of glass as additive.…”

Characterization of Phase formation and Microstructural Evolution on Dielectric Properties of SrO-B2O3-SiO2 and BaO-SrO-Nb2O5-B2O3-SiO2 glasses

“…The addition of Nb2O5 as nucleating agent contributed to the presence of crystallization phase, thus promote the grain growth of the glass [9]. According to Ab Rahman et al [10], they stated that high dielectric constant was attributed to high density bulk body and also the average grain size of materials. Thus, the grain that growth for BSNBS glass ceramics after heat treatment process contributed to the high dielectric constant of this material.…”

“…After that, glass ceramics materials were introduced where these materials have their advantages which free of porosity, and thus, their electrical breakdown strength might be higher than conventional ceramic dielectric materials [5][6][7]. They also may have high dielectric constant which is from the precipitated ceramic phases.Dielectric properties (dielectric constant and dielectric loss) of dielectric materials were always related to the density of bulk body [8]. Even though dielectric constant improves linearly with the increase of density, suitable crystallization phase is more effective to improve the dielectric constant of glass.…”