scholarly journals Mechanochemical synthesis of bismuth ferrite

2013 ◽  
Vol 49 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Z. Marinkovic-Stanojevica ◽  
L. Mancic ◽  
T. Sreckovic ◽  
B. Stojanovic
Keyword(s):  
Milling Time ◽  
Structure Refinement ◽  
Bismuth Ferrite ◽  
Renewable Energy Sources ◽  
Microstructural Analysis ◽  
Three Dimensional ◽  
Conventional Solid State Reaction ◽  
Refinement Method ◽  
Crystallite Sizes ◽  
Size And Morphology

A powder mixture of Bi2O3 and Fe2O3 was mechanically treated in a planetary ball mill in an air from 30 to 720 minutes. It was shown that the mechanochemical formation of BiFeO3 (BFO) phase was initiated after 60 min and its amount increased gradually with increasing milling time. A detailed XRPD structural analysis is realized by Rietveld?s structure refinement method. The resulting lattice parameters, relative phase abundances, crystallite sizes and crystal lattice microstrains were determined as a function of milling time. Microstructural analysis showed a little difference in morphology of obtained powders. The primary particles, irregular in shape and smaller than 400 nm are observed clearly, although they have assembled together to form agglomerates with varying size and morphology. Dense BFO ceramics were prepared by conventional solid-state reaction at the temperature of 810?C for 1h followed immediately by quenching process. [Projekat Ministarstva nauke Republike Srbije, br. III45007: Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processing

scholarly journals High-resolution three-dimensional microstructural analysis of cortex of the superolateral femoral neck in men reveals critical subregion

Bone Reports ◽  
2021 ◽  
Vol 14 ◽  
pp. 100964
Author(s):  
Ana Cirovic ◽  
Aleksandar Cirovic ◽  
Vladimir Zivkovic ◽  
Slobodan Nikolic ◽  
Petar Milovanovic ◽  
...  
Keyword(s):  
High Resolution ◽  
Femoral Neck ◽  
Microstructural Analysis ◽  
Three Dimensional

scholarly journals Understanding Starch Structure: Recent Progress

Agronomy ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 56 ◽  
Author(s):  
Eric Bertoft
Keyword(s):  
Cluster Model ◽  
Three Dimensional ◽  
Basic Structure ◽  
Dimensional Structure ◽  
Starch Granules ◽  
Growth Rings ◽  
Starch Structure ◽  
Internal Structures ◽  
Size And Morphology ◽  
Amylopectin Structure

Starch is a major food supply for humanity. It is produced in seeds, rhizomes, roots and tubers in the form of semi-crystalline granules with unique properties for each plant. Though the size and morphology of the granules is specific for each plant species, their internal structures have remarkably similar architecture, consisting of growth rings, blocklets, and crystalline and amorphous lamellae. The basic components of starch granules are two polyglucans, namely amylose and amylopectin. The molecular structure of amylose is comparatively simple as it consists of glucose residues connected through α-(1,4)-linkages to long chains with a few α-(1,6)-branches. Amylopectin, which is the major component, has the same basic structure, but it has considerably shorter chains and a lot of α-(1,6)-branches. This results in a very complex, three-dimensional structure, the nature of which remains uncertain. Several models of the amylopectin structure have been suggested through the years, and in this review two models are described, namely the “cluster model” and the “building block backbone model”. The structure of the starch granules is discussed in light of both models.

Protoenstatite: a crystal-structure refinement at 1100°C

1971 ◽  
Vol 134 (3-4) ◽  
Author(s):  
Joseph R. Smyth
Keyword(s):  
Crystal Structure ◽  
Melting Point ◽  
Single Crystal ◽  
Structure Refinement ◽  
Three Dimensional ◽  
Intensity Data ◽  
Crystal Structure Refinement ◽  
Space Group

AbstractTechniques allowing single-crystal investigations on the precession camera up to the melting point of platinum have been developed. The crystal structure of protoenstatite has been refined from three-dimensional intensity data obtained at 1100°C using a crystal of enstatite from the Norton County, Kansas meteorite. The space group is

scholarly journals Microstructural analysis of three-dimensional canal network in the rabbit lumbar vertebral endplate

2014 ◽  
Vol 33 (2) ◽  
pp. 270-276 ◽  
Author(s):  
Tomonori Yamaguchi ◽  
Shota Goto ◽  
Yasuhiro Nishigaki ◽  
Alejandro A. Espinoza Orías ◽  
Won C. Bae ◽  
...  
Keyword(s):  
Microstructural Analysis ◽  
Three Dimensional ◽  
Vertebral Endplate ◽  
Canal Network

scholarly journals Subsolidus solution and ionic conductivity of rock-salt structured Li3+5xTa1−xO4 electroceramics

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
S. Shari ◽  
K.B. Tan ◽  
C.C. Khaw ◽  
Z. Zainal ◽  
O.J. Lee ◽  
...  
Keyword(s):  
Rock Salt ◽  
Xrd Analysis ◽  
Secondary Phases ◽  
Ionic Conductors ◽  
Rock Salt Structure ◽  
Conventional Solid State Reaction ◽  
Salt Structure ◽  
Crystallite Sizes ◽  
Symmetry Space ◽  
Symmetry Space Group

AbstractLithium tantalate solid solution, Li3+5xTa1−xO4 was prepared by conventional solid-state reaction at 925 °C for 48 h. The XRD analysis confirmed that these materials crystallized in a monoclinic symmetry, space group C2/C and Z = 8, which was similar to the reported International Crystal Database (ICDD), No. 98-006-7675. The host structure, β-Li3TaO4 had a rock-salt structure with a cationic order of Li+:Ta5+ = 3:1 over the octahedral sites. A rather narrow subsolidus solution range, i.e. Li3+5xTa1−xO4 (0 ⩽ x ⩽ 0.059) was determined and the formation mechanism was proposed as a replacement of Ta5+ by excessive Li+, i.e. Ta5+ ↔ 5Li+. Both Scherrer and Williamson-Hall (W-H) methods indicated the average crystallite sizes in the range of 31 nm to 51 nm. Two secondary phases, Li4TaO4:5 and LiTaO3 were observed at x = 0.070 and x = −0:013, respectively. These materials were moderate lithium ionic conductors with the highest conductivity of ~2.5 × 10−3 Ω 1 ˙cm−1 at x = 0, at 0 °C and 850 °C; the activation energies were found in the range of 0.63 eV to 0.68 eV.

Preparation of High Density BaZr0.97Y0.03O3-δ Ceramic and its Interaction with Titanium Melt

2018 ◽  
Vol 768 ◽  
pp. 261-266 ◽  
Author(s):  
Ju Yun Kang ◽  
Guang Yao Chen ◽  
Bao Tong Li ◽  
Zi Wei Qin ◽  
Xiong Gang Lu ◽  
...  
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Milling Time ◽  
Sintered Pellet ◽  
Conventional Solid State Reaction ◽  
Industrial Grade ◽  
Minimum Particle Size ◽  
Ni Alloy ◽  
Improved Stability ◽  
Ball Milling Time

In this paper, the BaZrO3(BZ) and BaZr0.97Y0.03O3-δ(BZY3) powders were prepared by using the industrial grade BaCO3, ZrO2and Y2O3powders combining the conventional solid state reaction. The BaZrO3(BZ) and BaZr0.97Y0.03O3-δ(BZY3) ceramics were fabricated at 1750°C. The effect of ball milling time and sintering aid (TiO2) on the sinterability of BaZr0.97Y0.03O3-δ(BZY3) ceramics were investigated, and the improved stability of BaZrO3refractory with Y2O3additive were studied according to the refractory-metal interaction. The results revealed that the particle size of BZY3 powders decreased first and then increased with the increasing of ball milling time from 6h to 12h, and the minimum particle size was only 2.252μm at 8h. When 2wt.%TiO2was added, the sintered pellet of BZY3 was the most densest and the relative density was above 95%. After melting the Ti2Ni alloy on the BZY and BZ ceramics, the thickness erosion layer of BaZrO3and BZY3refractories and Ti2Ni alloy is approximately 50μm and 20μm respectively, showing that BZY3 was more stable than BaZrO3refractory.

A new luminescent host material K3GdB6O12: synthesis, crystal structure and luminescent properties activated by Sm3+

2018 ◽  
Vol 233 (6) ◽  
pp. 411-419 ◽  
Author(s):  
Dan Zhao ◽  
Cong-Kui Nie ◽  
Ye Tian ◽  
Bao-Zhong Liu ◽  
Yun-Chang Fan ◽  
...  
Keyword(s):  
Solid State ◽  
Uv Light ◽  
Three Dimensional ◽  
Visual Display ◽  
Luminescent Properties ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Promising Candidate ◽  
Conventional Solid State Reaction ◽  
Host Matrix

Abstract A new borate compound K3GdB6O12 has been prepared using a high temperature flux method and structurally characterized by single crystal X-ray diffraction analysis. The structure can be described as a three-dimensional framework that is composed of [B5O10]5− groups, K+ ions and Gd3+ ions. In this structure, one crystallographic distinct site is mixed occupied by K and Gd atoms at the molar ratio of 1:1. Furthermore, Sm3+ ion was used as the activator to test primary of K3GdB6O12 to be used as a luminescent host matrix. A series of phosphors K3Gd1−xB6O12:xSm3+ were synthesized by conventional solid-state reaction. The photoluminescence properties and concentration quenching of the prepared phosphors were investigated. The results show that K3Gd1−xB6O12:xSm3+ can be efficiently excited by near-UV light. K3Gd1−xB6O12:xSm3+ might be a promising candidate for visual display and solid-state lighting as an orange emission phosphor.

Experimental Investigation on Synthesis of Nanocrystalline Hydroxyapatite by the Mechanochemical Method

2018 ◽  
Vol 775 ◽  
pp. 149-155 ◽  
Author(s):  
Manu Harilal ◽  
A. Saikiran ◽  
N. Rameshbabu
Keyword(s):  
Milling Time ◽  
X Ray Diffraction ◽  
Mechanochemical Method ◽  
Transmission Electron ◽  
Nanocrystalline Hydroxyapatite ◽  
Size And Morphology ◽  
Time Required ◽  
Ceramic Compounds ◽  
Complete Formation ◽  
Thermal Stability Of

Mechanochemical synthesis is a simple and effective method to prepare ceramic compounds with nanosize. The present work was aimed at investigating the application of the mechanochemical method to synthesize nanocrystalline hydroxyapatite (HA). The shortest milling time required for synthesizing HA, using Ca (OH)2 and (NH4)2HPO4 as precursor materials was also established. The synthesized samples were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) to determine the phases evolved, functional groups present and to assess the size and morphology of the particles, respectively. Further, the thermal stability of the synthesized powders was investigated by heating to a temperature of 900 °C with a dwell time of 2 h. The broadening of the XRD peaks was used to find out the crystallite size and Williamson-Hall plots were used to estimate the lattice strain. The XRD and FTIR results demonstrated that the complete formation of the HA phase by mechanochemical method has started within a milling time of 30 min using Ca (OH)2 and (NH4)2HPO4 as precursors and the Ca/P ratio of the HA increased with increasing milling time. The TEM micrographs demonstrated that the HA particles are nanosized, non-spherical and highly agglomerated.

Structure and Electrical Characteristics of BaTiO3 and Ba0.99Er0.01TiO3 Ceramics

2018 ◽  
Vol 280 ◽  
pp. 127-133 ◽  
Author(s):  
F. A. Ismail ◽  
Rozana Aina Maulat Osman ◽  
Mohd Sobri Idris ◽  
N.A.M. Ahmad Hambali
Keyword(s):  
Perovskite Phase ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
Grain Sizes ◽  
Capacitance Voltage ◽  
Ion Incorporation ◽  
Voltage Breakdown

Conventional solid state reaction method was used to prepare BaTiO3 and Ba0.99Er0.01TiO3 ceramics. Influence of Er3+ ion incorporation on their structural, microstructural and electrical properties was studied. The phase pure samples were obtained when heated at 1400 °C for overnight. The tetragonal perovskite phase of BaTiO3 and Ba0.99Er0.01TiO3 was confirmed by using X-ray Diffraction (XRD) analysis which is in agreement with results obtained from Rietveld refinement analysis. The lattice parameters and unit cell volume of BaTiO3 increased when doped with Erbium. Microstructural analysis of BaTiO3 and Ba0.99Er0.01TiO3 ceramics showed that the grain sizes of BaTiO3 and Ba0.99Er0.01TiO3 significantly decreased. The dielectric properties of BaTiO3 and Ba0.99Er0.01TiO3 were investigated as a function of temperature and frequency. It revealed that the Curie temperature (TC) increased by doping Er content from 110 °C to 120 °C. Ba0.99Er0.01TiO3 exhibited the high value of dielectric constant (ε=5929) at TC of 120 °C. The capacitance-voltage characteristic revealed that the voltage breakdown for both BaTiO3 and Ba0.99Er0.01TiO3 exceeded 30 V.

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