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.

scholarly journals Effect of Milling Parameters on the Development of a Nanostructured FCC–TiNb15Mn Alloy via High-Energy Ball Milling

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1225
Author(s):  
Cristina García-Garrido ◽  
Ranier Sepúlveda Sepúlveda Ferrer ◽  
Christopher Salvo ◽  
Lucía García-Domínguez ◽  
Luis Pérez-Pozo ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Ball Mill ◽  
Milling Time ◽  
High Energy ◽  
Planetary Mill ◽  
Nominal Composition ◽  
Mechanically Alloyed ◽  
Milling Parameters ◽  
Energy Ball ◽  
Full Conversion

In this work, a blend of Ti, Nb, and Mn powders, with a nominal composition of 15 wt.% of Mn, and balanced Ti and Nb wt.%, was selected to be mechanically alloyed by the following two alternative high-energy milling devices: a vibratory 8000D mixer/mill® and a PM400 Retsch® planetary ball mill. Two ball-to-powder ratio (BPR) conditions (10:1 and 20:1) were applied, to study the evolution of the synthesized phases under each of the two mechanical alloying conditions. The main findings observed include the following: (1) the sequence conversion evolved from raw elements to a transitory bcc-TiNbMn alloy, and subsequently to an fcc-TiNb15Mn alloy, independent of the milling conditions; (2) the total full conversion to the fcc-TiNb15Mn alloy was only reached by the planetary mill at a minimum of 12 h of milling time, for either of the BPR employed; (3) the planetary mill produced a non-negligible Fe contamination from the milling media, when the highest BPR and milling time were applied; and (4) the final fcc-TiNb15Mn alloy synthesized presents a nanocrystalline nature and a partial degree of amorphization.

scholarly journals Mechanosynthesis of the Whole Y1−xBixMn1−xFexO3 Perovskite System: Structural Characterization and Study of Phase Transitions

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1515 ◽  
Author(s):  
Jose Ángel Quintana-Cilleruelo ◽  
Vignaswaran K. Veerapandiyan ◽  
Marco Deluca ◽  
Miguel Algueró ◽  
Alicia Castro
Keyword(s):  
Phase Transitions ◽  
Structural Characterization ◽  
Perovskite Phase ◽  
Ambient Pressure ◽  
Structural Evolution ◽  
High Energy ◽  
Planetary Mill ◽  
Nanocrystalline Powders ◽  
X Ray ◽  
Gradual Evolution

Perovskite BiFeO3 and YMnO3 are both multiferroic materials with distinctive magnetoelectric coupling phenomena. Owing to this, the Y1−xBix Mn1−xFexO3 solid solution seems to be a promising system, though poorly studied. This is due to the metastable nature of the orthorhombic perovskite phase of YMnO3 at ambient pressure, and to the complexity of obtaining pure rhombohedral phases for BiFeO3-rich compositions. In this work, nanocrystalline powders across the whole perovskite system were prepared for the first time by mechanosynthesis in a high-energy planetary mill, avoiding high pressure and temperature routes. Thermal decomposition temperatures were determined, and structural characterization was carried out by X-ray powder diffraction and Raman spectroscopy on thermally treated samples of enhanced crystallinity. Two polymorphic phases with orthorhombic Pnma and rhombohedral R3c h symmetries, and their coexistence over a wide compositional range were found. A gradual evolution of the lattice parameters with the composition was revealed for both phases, which suggests the existence of two continuous solid solutions. Following bibliographic data for BiFeO3, first order ferroic phase transitions were located by differential thermal analysis in compositions with x ≥ 0.9. Furthermore, an orthorhombic-rhombohedral structural evolution across the ferroelectric transition was characterized with temperature-dependent X-ray diffraction.

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.

Effect of Sintering Temperature on the Dielectric Properties of Pb(Zr0.52Ti0.48)O3 Ceramics Synthesized via High Planetary Ball Mill

2015 ◽  
Vol 1087 ◽  
pp. 167-171
Author(s):  
Mohd Fariz Ab Rahman ◽  
Asyraf bin Arshad ◽  
Zainal Arifin Ahmad ◽  
Julie Juliewatty Mohamed
Keyword(s):  
Dielectric Properties ◽  
Ball Mill ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Perovskite Phase ◽  
Secondary Phase ◽  
Planetary Mill ◽  
Dielectric Constants ◽  
Planetary Ball Mill ◽  
Increasing Temperature

The properties of Pb(Zr0.52Ti0.48)O3(PZT) ceramics have been studied. PZT ceramic powders were successfully prepared by high planetary ball mill method under different milling time and then were sintered at different sintering temperature. The raw materials of PbO, ZrO2 and TiO2, powders were ball milled at 40 and 60 hours using high planetary mill. The mixing powders then were compacted and sintered at 950°C and 1200°C. Formations of the perovskite phase along with some secondary phase were seen after 40 and 60 hours of milling while single phase formation of PZT was seen after sintered at both sintering temperatures. The grain size of the samples becomes larger with the increasing temperature. In dielectric properties analysis, the dielectric constants were reduced due to increasing sintering temperature. Meanwhile, the loss tangents increased with sintering temperature.

In Situ Combustion Synthesis in Air of Calcium Titanate Powders Using Minerals as a Calcium Source

2020 ◽  
Vol 982 ◽  
pp. 20-25
Author(s):  
Sukanya Rongsawat ◽  
Wannika Bunma ◽  
Tawat Chanadee
Keyword(s):  
Simultaneous Thermal Analysis ◽  
High Energy ◽  
Calcium Titanate ◽  
Calcium Source ◽  
Sequential Mechanism ◽  
Ft Ir ◽  
Calcium Sources ◽  
Using Data ◽  
Lime Stone

Calcium titanate (CaTiO3) was synthesized through combustion in air from calcium sources of raw minerals (lime-stone and calcite), anatase titanium dioxide (A-TiO2) and magnesium (Mg). The syntheses were divided into two reactant systems (lime-stone/A-TiO2/Mg and calcite/A-TiO2/Mg. Before synthesis, the raw minerals and A-TiO2 were high-energy milled for 30 min. These powders were then separately mixed with Mg by ball milling. After synthesis, the as-combusted products were leached with 2 M HCl solution to remove by-products and impurities. A sequential mechanism for the in-situ combustion was proposed by using data from simultaneous thermal analysis (STA) together with thermodynamic values calculated with HSC software. XRD results showed that the as-leached products from both reactant systems mainly contained CaTiO3. FT-IR spectroscopy indicated that the as-leached products had Ca-Ti-O and Ti-O functional groups. In addition, SEM observation of the as-leached products revealed cuboid-like crystals with a particle size of about 100 nm.

EFFECT OF BORON ON THE COMBUSTION CHARACTERISTICS OF METALLIZED HIGH-ENERGY MATERIALS

2020 ◽  
Author(s):  
A. Korotkikh ◽  
◽  
I. Sorokin ◽  
◽  
Keyword(s):  
Specific Impulse ◽  
Equilibrium Composition ◽  
Combustion Products ◽  
High Energy ◽  
Combustion Characteristics ◽  
Solid Propellants ◽  
Energy Materials ◽  
High Energy Materials ◽  
Condensed Combustion Products ◽  
Active Fuel Binder

The paper presents the results of thermodynamic calculations of the effect of pure boron additives on combustion characteristics of high-energy materials (HEM) based on ammonium perchlorate, ammonium nitrate, active fuel-binder, and powders of aluminum Al, titanium Ti, magnesium Mg, and boron B. The combustion parameters and the equilibrium composition of condensed combustion products (CCPs) of HEM model compositions were obtained with thermodynamic calculation program “Terra.” The compositions of solid propellants with different ratios of metals (Al/B, Ti/B, Mg/B, and Al/Mg/B) were considered. The combustion temperature Tad in a combustion chamber, the vacuum specific impulse J at the nozzle exit, and the mass fraction ma of the CCPs for HEMs were determined.

Melt Modification and Microstructure Homogeneity of Solidified TiC-TiB2 Composites Prepared by Combustion Synthesis in Ultrahigh Gravity Field

2013 ◽  
Vol 833 ◽  
pp. 125-129
Author(s):  
Hao Zhang ◽  
Zhong Min Zhao ◽  
Long Zhang ◽  
Shuan Jie Wang
Keyword(s):  
Gravity Field ◽  
Combustion Synthesis ◽  
Stokes Flow ◽  
High Energy ◽  
Adiabatic Temperature ◽  
Full Density ◽  
Reactive System ◽  
Refined Microstructure ◽  
Ultrafine Grained ◽  
Ultrafine Grained Microstructure

By introducing (CrO3+Al) high-energy thermit into (Ti+B4C) system and designing adiabatic temperature of reactive system as 3000°C,3200°C, 3400°C, 3600°C and 3800°C respectively, a series of solidified TiC-TiB2were prepared by combustion synthesis in ultrahigh gravity field with the acceleration 2000 g. XRD, FESEM and EDS results showed that the solidified TiCTiB2were composed of a number of TiB2primary platelets, irregular TiC secondary grains, and a few of isolated Al2O3inclusions and Cr-based alloy. Because of the enhanced Stokes flow in mixed melt with the increased adiabatic temperature, Al2O3droplets were promoted to float up and separate from TiC-TiB2-Me liquid while constitutional distribution became more and more uniform in TiC-TiB2-Me liquid, resulting in not only the sharply-reduced Al2O3inclusions in the solidified ceramic but also the refined microstructure and the improved homogeneity in the ceramic, and ultrafine-grained microstructure with a average thickness of TiB2platelets smaller than 1μm began to appear in near-full-density ceramic as the adiabatic temperature exceeded 3600°C, so the densification, fracture toughness and flexural strength of the ceramic were enhanced with the increased adiabatic temperature of the reactive system.

A Study of Exchange-Coupling Effect on Nd2Fe14B / α-Fe Forming Core/Shell Shape

2007 ◽  
Vol 119 ◽  
pp. 147-150 ◽  
Author(s):  
Chang Woo Kim ◽  
Young Hwan Kim ◽  
Don Keun Lee ◽  
In Chul Jeong ◽  
Hae Woong Kwon ◽  
...  
Keyword(s):  
Exchange Coupling ◽  
Ball Mill ◽  
Coupling Effect ◽  
Chemical Reduction ◽  
High Energy ◽  
Shell Shape ◽  
Core Shell ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Mill Process

We report the core/shell type as the interesting one of the various techniques to prepare exchange-coupled permanent magnet. In this study, the exchange-coupled Nd2Fe14B/α-Fe was prepared by high energy ball mill process and chemical reduction. Nd15Fe77B8 powder prepared by high energy ball mill process was coated with α-Fe nanoparticle by chemical reduction. α-Fe nanoparticle on the ball milled Nd15Fe77B8 was synthesized by chemical reduction with borohydride as a reducing agent in aqueous solution. After annealing, Nd2Fe14B/α-Fe forming core/shell shape has exchange-coupling effect and was identified by using XRD, FE-SEM, VSM, TMA and EDX.

Increasing of Energy-Power Indicators of Mechanical Processing in a Planetary Mill by the Use of a Working Chamber with a Square Shape of the Internal Cavity

2020 ◽  
Vol 299 ◽  
pp. 447-451 ◽  
Author(s):  
V.G. Gusev ◽  
A.V. Sobolkov ◽  
A.V. Aborkin
Keyword(s):  
High Efficiency ◽  
Computational Study ◽  
High Energy ◽  
Planetary Mill ◽  
Internal Cavity ◽  
Cylindrical Shape ◽  
Mechanical Processing ◽  
Discrete Elements ◽  
Working Chamber ◽  
Processing Regimes

The paper presents the results of a computational study of the influence of the geometry of the working chamber on the energy-force interaction of grinding bodies in the process of the mixture processing in a planetary mill. The method of computer simulation, using the software system, based on the ideology of discrete elements, shows the high efficiency of processing in a planetary mill, using a working chamber with a square-shaped cavity. The values of the factors that have a dominant influence on the mechanical processing of the charge are determined. A comparison with the process of processing in the working chamber of the traditional cylindrical shape is made. The research results will be used in the appointment of large-size charge processing regimes that provide a high-energy grinding process.

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