scholarly journals Calcium titanate ceramics obtained by combustion synthesis and two-step sintering

2020 ◽  
Vol 52 (4) ◽  
pp. 491-502
Author(s):  
Kanchana Maitreekeaw ◽  
Tawat Chanadee
Keyword(s):  
Dielectric Constant ◽  
Combustion Synthesis ◽  
Xrd Analysis ◽  
Calcium Titanate ◽  
Single Step ◽  
Dielectric Constants ◽  
Sintered Ceramic ◽  
Relaxation Polarization ◽  
Titanate Ceramics ◽  
Titanate Ceramic

Calcium titanate powder was successfully prepared from duck eggshell and anatase titanium dioxide with a magnesium inductant via combustion synthesis in argon. As-combusted products were leached with diluted HCl. In XRD analysis, as-leached powders exhibited a major phase of CaTiO3 with a perovskite structure. The particle size, observed by SEM, was approximately 240 nm. As-leached powders were densified by single-step (SST) and two-step sintering (TSS) to produce calcium titanate ceramics. The first step of all TSS conditions was fixed at 1350C and holding times (t1) at this temperature were varied up to 120 min. Calcium titanate ceramic obtained from holding for 120 min had a grain size of 2.18 ?m, relative density of 86.68% and a dielectric constant of 92. Two-step sintered ceramic had the highest density (95.73%) and best dielectric properties (dielectric constant = 110, dielectric loss = 0.02) when the holding temperature (T2) was 1250?C. Calcium titanate ceramics processed by two-step sintering had denser microstructures and higher dielectric constants than single-step sintered ceramic due to grain boundary diffusion and the simplicity of relaxation polarization.

An Investigation on the Mechanism of TiC+Al2O3 Formation in the Combustion Synthesis of the Mechanically Activated TiO2-Al-C System

2008 ◽  
Vol 273-276 ◽  
pp. 204-209
Author(s):  
Sayed Hamid Reza Fatemi Nayeri ◽  
Jalil Vahdati Khaki ◽  
Mohammad Reza Aboutalebi
Keyword(s):  
Combustion Synthesis ◽  
Powder Mixture ◽  
Titanium Aluminides ◽  
Milled Powder ◽  
Xrd Analysis ◽  
Single Step ◽  
Second Step ◽  
Particle Diffusion ◽  
Different Temperatures ◽  
Three Stages

A mechanism for the combustion synthesis of TiC+Al2O3 was proposed in a mechanically activated TiO2-Al-C system. As-milled powder mixture was analyzed using XRD and TEM techniques where no chemical reaction and/or inter-particle diffusion were identified. The results obtained from DTA tests on unmilled powder revealed that the combustion synthesis occurred in a single step at 962 °C while the synthesis of mechanically activated powder mixture occurred in three different stages. The XRD analysis on the synthesized samples of 8 hour premilled powder at different temperatures showed that the three stages were as follows: First the reaction between Al and TiO2 takes place forming Al3Ti, Ti2O3, and Al2O3 at 700 °C. In the second step, Ti-rich titanium aluminides (AlTi, AlTi2, and AlTi3) and TiO, are formed at 923 °C, and finally the formation of TiC+Al2O3 is completed at 1329 °C.

scholarly journals Electrically Insulating Plasma Polymer/ZnO Composite Films

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3099 ◽  
Author(s):  
Ahmed Al-Jumaili ◽  
Avishek Kumar ◽  
Kateryna Bazaka ◽  
Mohan V. Jacob
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Composite Structures ◽  
Composite Films ◽  
Single Step ◽  
Dielectric Constants ◽  
Plasma Polymer ◽  
Nanocomposite Films ◽  
Step Method ◽  
Metal Insulator Metal

In this report, the electrical properties of plasma polymer films functionalized with ZnO nanoparticles were investigated with respect to their potential applications in biomaterials and microelectronics fields. The nanocomposite films were produced using a single-step method that combines simultaneous plasma polymerization of renewable geranium essential oil with thermal decomposition of zinc acetylacetonate Zn(acac)2. The input power used for the deposition of composites were 10 W and 50 W, and the resulting composite structures were abbreviated as Zn/Ge 10 W and Zn/Ge 50 W, respectively. The electrical properties of pristine polymers and Zn/polymer composite films were studied in metal–insulator–metal structures. At a quantity of ZnO of around ~1%, it was found that ZnO had a small influence on the capacitance and dielectric constants of thus-fabricated films. The dielectric constant of films with smaller-sized nanoparticles exhibited the highest value, whereas, with the increase in ZnO particle size, the dielectric constant decreases. The conductivity of the composites was calculated to be in the in the range of 10−14–10−15 Ω−1 m−1, significantly greater than that for the pristine polymer, the latter estimated to be in the range of 10−16–10−17 Ω−1 m−1.

Effect of Neodymium and Samarium on the Properties of Bismuth Titanate Ceramics

2015 ◽  
Vol 761 ◽  
pp. 397-401
Author(s):  
Umar Al Amani Azlan ◽  
Ahmad Fauzi Mohd Noor ◽  
Yusliza Yusuf ◽  
Nooririnah Omar ◽  
Noraiham Mohamad
Keyword(s):  
Dielectric Constant ◽  
Single Phase ◽  
Bismuth Titanate ◽  
Pyrochlore Phase ◽  
Single Step ◽  
Phase Detection ◽  
Rare Earth Compounds ◽  
Low Dielectric ◽  
Calcination Step ◽  
Titanate Ceramics

This paper reported the doping effect on BIT by two different rare-earth compounds i.e. Nd and Sm, each at different mole content (0.25, 0.5, 0.75 and 1.0 mol). The so-called single-step combustion synthesis was used to produce the as-combusted powders, whereby the intermediate calcination step was then eliminated. This method was able to sinter the samples at temperature as low as 1000°C for 3 h. The entire ceramics were characterized for phase detection and stability, microstructure and dielectric properties. It was found that the single phase BIT was successfully formed with Nd and Sm doping. However, little content of pyrochlore phase was detected in the sample with Sm doping particularly at high mole content. (0.5 to 1.0 mol). Besides, a remarkable decrease in the grain size with better microstructure was observed particularly at high mole content (1.0). The improvement in microstructure led to the increase in dielectric constant with low dielectric loss.

RF Magnetron Sputtering Process for (Ba,Sr)TiO3 Thin Films with Higher Dielectric Constant

2003 ◽  
Vol 784 ◽  
Author(s):  
T. Jimbo ◽  
I. Kimura ◽  
Y. Nishioka ◽  
K. Suu
Keyword(s):  
Dielectric Constant ◽  
Magnetron Sputtering ◽  
Film Thickness ◽  
Deposition Temperature ◽  
Gas Flow ◽  
Rf Magnetron Sputtering ◽  
Xrd Analysis ◽  
Film Properties ◽  
Sintered Ceramic ◽  
Bst Films

ABSTRACT(Ba,Sr)TiO3 (BST) films were deposited by RF magnetron sputtering using BST sintered ceramic targets and an approach to deposit BST films with higher permittivity by sputtering deposition was explored aiming to the application of thin film capacitor, RF tunable components and so on.Basic sputtering conditions such as RF power, deposition temperature and so on were varied in this study. BST films and Pt/BST/Pt capacitors were investigated by electrical properties, XRD analysis and SEM observation. It became clear that deposition temperature, deposition rate, and BST film thickness were important parameters for optimization of the dielectric constant. From the non-linearly relationship between dielectric constant and BST film thickness, we could also find that the interfacial layer between BST and Pt bottom electrode was important for controlling the BST film properties. Furthermore, an approach to enhance the crystalline quality has to be explored for further improvement of BST film properties. Dielectric constant could be raised up to 10% by just changing the gas flow sequence of BST sputtering process.

Chemical Composition-Microstructure-Dielectric Constant Relations of Mg-Doped Calcium Titanate Synthesized by Solid State Reaction Technique

2017 ◽  
Vol 751 ◽  
pp. 390-396
Author(s):  
Oratai Jongprateep ◽  
Nicha Sato ◽  
Jednupong Palomas ◽  
Pongsakorn Jantaratana
Keyword(s):  
Dielectric Constant ◽  
Chemical Composition ◽  
Solid State ◽  
Solid State Reaction ◽  
Secondary Phase ◽  
Dielectric Materials ◽  
Calcium Titanate ◽  
Dielectric Constants ◽  
Composition Analysis ◽  
X Ray Diffraction

It has been generally accepted that doping of dielectric materials could significantly contribute to compositional and microstructural evolution, which consequently lead to alteration in dielectric properties. In this study, the effects of adding magnesium (Mg) at 5,10 and 20at% on the chemical composition, microstructure and dielectric constant of calcium titanate (CaTiO3) synthesized by solid state reaction was assessed. Chemical composition analysis using an X-ray diffraction technique CaTiO3 doped with 5 at% Mg has been found to contain a single phase whereas samples doped with 10 and 20 at% Mg both exhibited apparent secondary phase (MgO). Microstructural examination however, revealed that no significant variation in particle size, grain size and density were evident among the samples of different Mg contents. Average dielectric constants obtained from the entire samples ranged from 245.9 to 387.6 (at 1 MHz) and the sample with the highest dielectric constant was that doped with 5 at% Mg. Enhancement of dielectric constant in the samples with the lowest level of Mg doping has been attributed largely to the homogeneity of its chemical composition.

Microstructures and Dielectric Constants of Ba0.05SrxCa0.95-xTiO3 (x=0, 0.225, 0.475, 0.725 and 0.95) Synthesized by the Solution Combustion Technique

2018 ◽  
Vol 766 ◽  
pp. 197-204
Author(s):  
Oratai Jongprateep ◽  
Nicha Sato ◽  
Sansanee Boonsalee ◽  
Jae Hwan Pee
Keyword(s):  
Dielectric Constant ◽  
Fine Particles ◽  
Dielectric Material ◽  
Grain Morphology ◽  
Calcium Titanate ◽  
Dielectric Constants ◽  
Solution Combustion ◽  
Strontium Content ◽  
Barium Strontium ◽  
Combustion Technique

Barium strontium calcium titanate is a dielectric material exploited in fabrication of electronic devices such as capacitors, signal filters and satellite components. Dielectric properties can be enhanced through compositional and microstructural control. This study, therefore, aimed at synthesizing barium strontium calcium titanate (Ba0.05SrxCa0.95-xTiO3, where x = 0, 0.225, 0.475, 0.725 and 0.95) powders by a solution combustion technique. The powders were pressed, sintered at 1450°C and tested for their properties. Experimental results revealed that strontium content did not significantly influence chemical composition, particle sizes and density. All powders exhibited a single phase corresponding to Ba0.05SrxCa0.95-xTiO3with fine particles with the average size smaller than 0.4 micrometer. All sintered samples had density higher than 95% of theoretical density. On the contrary, the results indicated that strontium content affected grain size, grain morphology and dielectric constant of the sintered samples. The highest dielectric constant of 531 (at 1 MHz) was achieved in the Ba0.05Sr0.225Ca0.725TiO3. Dielectric constant was discussed with respect to microstructure.

High Temperature Dielectric Properties of Sol-Gel Derived Thick PZT thin Films with Different Zr/Ti Atom Ratios

2001 ◽  
Vol 688 ◽  
Author(s):  
Jinrong Cheng ◽  
Wenyi Zhu ◽  
Nan Li ◽  
L.Eric Cross
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Remnant Polarization ◽  
Elevated Temperatures ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Dielectric Constants ◽  
Silicon Substrates ◽  
Pzt Thin Films ◽  
Pzt Films

AbstractPZT thin films of different thicknesses and Zr/Ti ratios of 60/40, 52/48 and 45/55 were coated onto platinized silicon substrates by using 2 methoxyethanol (2-MOE) based sol-gel spinon technique and crystallized with a rapid thermal annealing (RTA) process. XRD analysis revealed that thin PZT films exhibit random texture, while the thicker ones exhibit (100) texture, which was independent of composition. Dielectric constants and dissipation factors of PZT thin films were measured at elevated temperatures and as a function of frequency. For films with a thickness of ∼ 4 μm, the Curie points are at 350, 375 and 422°C for Zr/Ti ratios of 60/40, 52/48 and 45/55, respectively. All these films exhibit a high remnant polarization. A remnant polarization of 35 μC/cm2 had been achieved for the 60/40 films. No enhancement of the dielectric constant was observed in films with a composition close to MPB. The higher dielectric constant observed in films with the highest Zr content was explained by the concept of domain engineering.

scholarly journals Calcium Titanate from Food Waste: Combustion Synthesis, Sintering, Characterization, and Properties

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Siriluk Cherdchom ◽  
Thitiwat Rattanaphan ◽  
Tawat Chanadee
Keyword(s):  
Combustion Synthesis ◽  
Ball Mill ◽  
Perovskite Phase ◽  
Combustion Products ◽  
High Energy ◽  
Calcium Titanate ◽  
Planetary Mill ◽  
Structural Defects ◽  
Calcium Source ◽  
Titanate Ceramic

Calcium titanate (CaTiO3) was combustion synthesized from a calcium source of waste duck eggshell, anatase titanium dioxide (A-TiO2), and magnesium (Mg). The eggshell and A-TiO2 were milled for 30 min in either a high-energy planetary mill or a conventional ball mill. These powders were then separately mixed with Mg in a ball mill. After synthesis, the combustion products were leached and then sintered to produce CaTiO3 ceramic. Analytical characterization of the as-leached combustion products revealed that the product of the combustion synthesis of duck eggshell + A-TiO2 that had been high-energy-milled for 30 min before synthesis comprised a single perovskite phase of CaTiO3. The high-energy milling of the reactant powder had generated a large reactive surface area and induced structural defects, both of which drove the completion of the combustion reaction and the phase conversion of the reactants into the product. A calcium titanate ceramic, fabricated by sintering as-leached powdered combustion product at 1350°C for 180 min, achieved a maximum density of 3.65 g/cm3 and a minimum porosity of 0.54%. The same fabricated calcium titanate ceramic product also exhibited the highest dielectric constant (∼78) and the lowest dielectric loss (∼0.02), which resulted from the simplified charge polarization process.

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