Thermal Analysis of Ca1+xCu3Ti4O12+x Precursor in Nitrogen and Oxygen Environment at 1000 °C

2020 ◽  
Vol 1010 ◽  
pp. 268-273
Author(s):  
Julie Juliewatty Mohamed ◽  
Noruzaman Daud ◽  
Mohamad Johari bin Abu ◽  
Mohd Fariz Ab Rahman ◽  
Siti Roshayu binti Hassan ◽  
...  
Keyword(s):  
Mass Loss ◽  
Room Temperature ◽  
Single Phase ◽  
Xrd Analysis ◽  
Phase Changes ◽  
Oxygen Absorption ◽  
Atmospheric Gases ◽  
Scanning Calorimetry ◽  
Nitrogen Gas ◽  
Ca Ions

The thermal kinetic analyses are prepared on Ca1+xCu3Ti4O12+x powders using simultaneous thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) measurement in a dual atmospheric gases environment. Initially, the nitrogen gas flowed from room temperature to 1000 °C, and then the environment was shifted and hold for 1 hour with oxygen. The result shows that the TGA patterns of the temperature and mass loss are disorderly with x values. The mass loss % patterns slightly decreased with increased additional Ca-based element. The decreased of oxygen absorption as the values of x increased also can be explained by the reduction of single-phase CCTO structure when excess Ca ions. The DSC pattern shows two prominent endothermic peaks and two exothermic peaks that relate to the melting point of the reactant and crystalline phase changes of samples, while the significant endothermic peak at 1000 °C is corresponding to the formation of CCTO compounds as identified by XRD analysis.

scholarly journals The Role of Polypropylene Microfibers in Thermal Properties and Post-Heating Behavior of Cementitious Composites

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2676
Author(s):  
Mohammad R. Irshidat ◽  
Nasser Al-Nuaimi ◽  
Mohamed Rabie
Keyword(s):  
Melting Point ◽  
Heat Flow ◽  
Mass Loss ◽  
Failure Modes ◽  
Cement Mortar ◽  
Xrd Analysis ◽  
Cementitious Composites ◽  
Polypropylene Fibers ◽  
Scanning Calorimetry ◽  
Heating Behavior

This paper experimentally studied the effect of polypropylene (PP) microfibers on thermal and post-heating mechanical behaviors of cementitious composites. Cement mortars with small dosage of polypropylene fibers were prepared, heated at various temperatures (150 °C, 200 °C, 450 °C, and 600 °C), and then tested. The investigated parameters include residual compressive and flexural strengths, elastic modulus, fracture energy, stress intensity factors, failure modes, microstructure (scanning electron microscopy (SEM) imaging), thermal conductivity, heat flow (differential scanning calorimetry (DSC) test), mass loss (thermogravimetric analysis (TGA) test), and chemical composition (XRD analysis). The results showed the efficiency of PP fibers to enhance the post-heating behavior and the residual mechanical properties of cement mortar after heating. The presence of PP fibers did not affect the heat flow and the mass loss of cement mortar at room temperature. However, heating cement mortar at temperature beyond the melting point of the fibers negatively affected its thermal behavior. The presence of PP fibers played a major role in bridging the cracks and mitigating their propagation. Once the melting point of the polypropylene fibers is exceeded, the fibers melted and created extra voids in the microstructure of concrete.

Discotic liquid crystals of transition metal complexes, part 36: syntheses and mesomorphic properties of very large discotic liquid crystals based on triphenylenocyanine and 1,4-diazatriphenylenocyanine

2006 ◽  
Vol 10 (09) ◽  
pp. 1145-1155 ◽  
Author(s):  
Masahiro Ichihara ◽  
Masakazu Miida ◽  
Bernhard Mohr ◽  
Kazuchika Ohta
Keyword(s):  
Liquid Crystals ◽  
Room Temperature ◽  
Optical Microscope ◽  
Decomposition Temperature ◽  
Discotic Liquid Crystals ◽  
Large Area ◽  
Scanning Calorimetry ◽  
Nitrogen Gas ◽  
Homeotropic Alignment ◽  
Mesomorphic Properties

Two series of very large discotic complexes of tetrakis (2,3,6,7-tetraalkoxy)triphenylenocyaninato copper(II) (abbreviated as ( C n O )16 TcCu ; n = 8, 10, 12 and 14) and tetrakis(2,3,6,7-tetraalkoxy)-1,4-diazatriphenylenocyaninato copper(II) (abbreviated as ( C n O )16 TzCu ; n = 8, 10, 12 and 14), were synthesized to investigate their mesomorphic properties by differential scanning calorimetry, thermogravimetry analysis, polarizing optical microscope observation and temperature-dependent X-ray studies. The results show that each of the ( C n O )16 TcCu derivatives exhibits two or three disordered rectangular columnar ( Col rd ) mesophases from room temperature to the decomposition temperature at ca. 330-340°C under nitrogen gas. However, each of the ( C n O )16 TzCu complexes exhibits only one ordered tetragonal columnar ( Col tet.o ) mesophase in an extremely wide temperature region from room temperature to the decomposition temperature at ca 300°C and ca. 340-350°C under the atmosphere and nitrogen gas, respectively. It is very interesting that the Col tet.o mesophase of ( C n O )16 TzCu for n = 10, 12 and 14 shows remarkable spontaneous homeotropic alignment in a large area, without disclinations and polydomains, in the temperature range from room temperature to the decomposition temperature. As far as we know, these discotic liquid crystals are the first examples to show homeotropic alignment at room temperature. Furthermore, the difference between the mesomorphic properties of ( C n O )16 TcCu and ( C n O )16 TzCu originated only from the additional eight nitrogen atoms in the central core in ( C n O )16 TzCu .

Chemically disordered Ni3Al synthesized by high vacuum evaporation

1991 ◽  
Vol 6 (10) ◽  
pp. 2019-2021 ◽  
Author(s):  
S.R. Harris ◽  
D.H. Pearson ◽  
C.M. Garland ◽  
B. Fultz
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Single Phase ◽  
High Vacuum ◽  
Liquid Nitrogen Temperature ◽  
Vacuum Evaporation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Average Grain Size

Films of chemically disordered fcc Ni3Al were synthesized by the vacuum evaporation of Ni3Al onto room temperature and liquid nitrogen temperature substrates. X-ray diffractometry and transmission electron microscopy showed the material to be single phase with an average grain size of about 4 nm. The formation of the equilibrium L12 ordered phase occurred simultaneously with grain growth at temperatures above 350°C. Differential scanning calorimetry provided ordering enthalpies of 7 kJ/mole and 9 kJ/mole for material evaporated onto room temperature and liquid nitrogen temperature substrates, respectively.

DIELECTRIC STUDIES OF SAMARIUM MODIFIED (Pb)(Zr, Ti, Fe, Nb)O3 CERAMIC SYSTEM

2009 ◽  
Vol 23 (11) ◽  
pp. 1437-1442 ◽  
Author(s):  
PRATIBHA SINGH ◽  
SANGEETA SINGH ◽  
J. K. JUNEJA ◽  
CHANDRA PRAKASH ◽  
K. K. RAINA
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Single Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Dielectric Studies ◽  
Dielectric Measurements ◽  
Ceramic System ◽  
Reaction Method ◽  
Room Temperature Dielectric Constant

Here we report the investigations on Sm -substituted PZTFN ( Pb 1-x Sm x Zr 0.588 Ti 0.392 Fe 0.01 Nb 0.01 O 3) (where x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) polycrystalline solid solutions fabricated by solid-state reaction method. XRD analysis shows all the samples to be single phase with tetragonal structure. Dielectric measurements were carried out in the temperature range 30°C–400°C at different frequencies in the range 100 Hz to 100 kHz. From the temperature variation of dielectric constant (ε), Curie temperature (TC) was determined which was found to decrease with increasing x. The room temperature dielectric constant (ε RT ) initially increases with increasing x and then starts decreasing. Dielectric loss improves with Sm -doping.

Investigation of CaCu3Ti4O12 Precursor by Simultaneous TGA and DSC Analysis in Oxygen Environment

2020 ◽  
Vol 1010 ◽  
pp. 228-232
Author(s):  
Noruzaman Daud ◽  
Julie Juliewatty Mohamed ◽  
Mohamad Johari bin Abu ◽  
Mohd Fariz Ab Rahman ◽  
Siti Roshayu binti Hassan ◽  
...  
Keyword(s):  
Heat Flow ◽  
Mass Loss ◽  
Phase Structure ◽  
Phase Changes ◽  
Atmospheric Gases ◽  
X Ray Diffraction ◽  
Peak Points ◽  
Oxygen Gas ◽  
Flow Changes ◽  
Tga And Dsc

CCTO consist of huge dielectric constant up to 105 at temperature range -173 °C to 326 °C becomes an attraction to investigate the CCTO ceramics. The samples were tested using simultaneous thermogravimetry (TGA) and differential calorimetry (DSC) measurement in dual atmospheric gases condition by flowing nitrogen and oxygen gas. Phase changes of CCTO precursor were analyzed by X-ray diffraction machine. The samples CT900 and CT1000 occur both of mass loss and reabsorption due to the oxygen-rich environment. The mass loss for both samples CT900 and CT1000 has complete curves of CaCO3 decomposition. Sample CT900 shows incomplete of heat flow changes compare to samples CTNML and CT1000. The result shows that the formation of the CCTO phase structure does not depend on the oxygen gas environment but also requires specific heat of energy and temperature to changes the phase structure. DSC graph shows two magnitudes of heat flow changes for sample CT1000 that are an endothermic at temperature peak points 824 °C and 984 °C.

Thermodynamic Interactions in Blends of Polydienes

1999 ◽  
Vol 72 (4) ◽  
pp. 580-586 ◽  
Author(s):  
Ramanan Krishnamoorti
Keyword(s):  
Small Angle Neutron Scattering ◽  
Room Temperature ◽  
Single Phase ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Binary Blends ◽  
Critical Solution Temperature ◽  
Dsc Measurements ◽  
Lcst Behavior ◽  
Mixed Microstructure

Abstract Thermodynamic interactions and phase behavior in binary blends of model mixed microstructure polybutadienes with model 1,4-polyisoprene were studied using small angle neutron scattering and differential scanning calorimetry (DSC). The microstructure of the polybutadiene ranged from 8% 1,2 (92% 1,4) to 90% 1,2 (10% 1,4) units, while the polyisoprene contained 93% 1,4 and 7% 3,4 units. The blends of protonated polybutadienes (HPB) with deuterated 1,4 polyisoprene (DPI) exhibited lower critical solution temperature (LCST) behavior when the polybutadiene contained 38 mol % or more of 1,2 units. Below this 1,2 content of the polybutadiene, all HPB/DPI blends were found to be phase separated at all temperatures above 25 °C. The DSC measurements revealed that other than a blend containing 8% 1,2-polybutadiene and (protonated) 1,4 polyisoprene, all other blends were single phase at room temperature. These results are understood in the context of previous work performed by Han and coworkers on deuterated polybutadiene-protonated polyisoprene blends.

Leaching of Plutonium from “Old” Samples of Single Phase Ceramics Based on Zr0.79Gd0.14Pu0.04O1.93 and La0.9Pu0.1PO4 Doped with 238Pu

MRS Advances ◽  
2016 ◽  
Vol 1 (63-64) ◽  
pp. 4249-4253 ◽  
Author(s):  
Bella Yu Zubekhina ◽  
Boris E. Burakov
Keyword(s):  
Mass Loss ◽  
Radiation Damage ◽  
Single Phase ◽  
Xrd Analysis ◽  
Distilled Water ◽  
High Radiation ◽  
Cubic Zirconia ◽  
Leach Test

ABSTRACTSamples of 238Pu-doped single-phase ceramics based on cubic zirconia, Zr0.79Gd0.14Pu0.07O1.93, and monazite, La0.9Pu0.1PO4, have been studied by static leach test in distilled water. Before leach test accumulated doses were (in alpha-decays/m3 x 1026): from 1.6 to 1.7 – for cubic zirconia; and 1.0 – for monazite. Despite high radiation damage both phases remained crystalline according to XRD analysis. The results of static leach tests demonstrate the following Pu normalized mass loss (in g/m2, 90°C, 28 days): from 0.3 to 0.7 – for cubic zirconia; and 1.6 – for monazite. These data are discussed in comparison with results of previous leach tests carried out at lower accumulated doses.

scholarly journals Oxidation kinetics of YBaCo 4 O 7+ δ and substituted oxygen carriers

2018 ◽  
Vol 5 (6) ◽  
pp. 180150
Author(s):  
Limin Hou ◽  
Qingbo Yu ◽  
Kun Wang ◽  
Qin Qin ◽  
Mengqi Wei ◽  
...  
Keyword(s):  
Oxidation Process ◽  
Solid Phase ◽  
Oxygen Carrier ◽  
Xrd Analysis ◽  
Phase Changes ◽  
Oxygen Absorption ◽  
Oxygen Carriers ◽  
Isothermal Tg ◽  
Primary Particles ◽  
Kinetics Of

In this paper, the relaxation kinetics of the oxidation process of the YBaCo 4 O 7+ δ , Y 0.95 Ti 0.05 BaCo 4 O 7+ δ and Y 0.5 Dy 0.5 BaCo 4 O 7+ δ oxygen carriers is studied with isothermal reaction data. XRD analysis for fresh samples shows that all the samples have YBaCo 4 O 7+ δ structure. Scanning electron microscopy images of samples show that the samples consist of porous agglomerates of primary particles. Isothermal TG experiments are conducted with temperatures of 290°C, 310°C, 330°C and 350°C, respectively. It is found that the Avrami-Eroféev model describes solid-phase changes in the oxygen absorption process adequately. The results show that the distributed activation energies of the oxidation process obtained by the Avrami-Eroféev model are 42.079 kJ mol −1 , 42.944 kJ mol −1 and 41.711 kJ mol −1 for the YBaCo 4 O 7+ δ , Y 0.95 Ti 0.05 BaCo 4 O 7+ δ and Y 0.5 Dy 0.5 BaCo 4 O 7+ δ oxygen carriers, respectively. The kinetic model was obtained to predict the oxygen carrier conversion of oxygen absorption for different time durations. The kinetic parameters obtained here are quite vital when this material is used in reactors.

scholarly journals Structural, Dielectric and Magnetic Properties of Al3+ and Cr3+ Substituted Ni-Zn-Cu Ferrites

2018 ◽  
Vol 4 (5) ◽  
pp. 487-491 ◽  
Author(s):  
G. Satyanarayana ◽  
G. Nageswara Rao ◽  
K. Vijaya Babu
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Single Phase ◽  
Fourier Transforms ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Pulse Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Loop Technique

Ferrite materials with the general formula Ni0.7Zn0.2Cu0.1Fe1.9M0.1O4 (M=Al and Cr) are synthesized by using the solid state reaction method. X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectra, scanning electron microscope (SEM) dielectric measurements and vibrating sample magnetometer (VSM) techniques are utilized to study the various properties of the synthesized ferrites. XRD analysis confirmed the formation of single phase cubic spinel structure and the crystallite size is calculated by Scherrer’s formula found to be 20.3 and 12.5 nm. The magnetic properties were studied using pulse field hysteresis loop technique at room temperature. The saturation magnetization exhibit 98.71 and 91.69 emu/g for Al3+ and Cr3+ substituted Ni-Zn-Cu ferrites respectively. The magnetic permeability is increasing for chromium substituted compound in the frequency range 100 Hz to 120 MHz and significant modification in DC conductivity is explained on the basis of hopping mechanism.

Miscibiuty in Blends of Polybenzimidazole and Fluorine Containing Polyimides

1989 ◽  
Vol 171 ◽  
Author(s):  
Hiroaki Yamaoka ◽  
Norman E. Aubrey ◽  
William J. MAcknight ◽  
Frank E. Karasz
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Phase Separation ◽  
Dynamic Mechanical Thermal Analysis ◽  
Room Temperature ◽  
Single Phase ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical

ABSTRACTBlends of polybenzimidazole (PBI) with either of two fluorine-containing polyimides were prepared by casting from solution and by precipitation. Dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) were used to study miscibility in the two blend systems.The blends of PBI with the first polyimide, the polysulfonimide Pl-1, consisted of a single phase when the blends contained less than 30 wt% Pl-1; above 50 wt% Pl-1, phase separation occurred even at room temperature. The PBI blends containing the second polyimide, Pl-2, were immiscible.

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