scholarly journals Study of Phase Formation Processes in Li2ZrO3 Ceramics Obtained by Mechanochemical Synthesis

Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 21
Author(s):  
Maxim V. Zdorovets ◽  
Artem L. Kozlovskiy ◽  
Baurzhan Abyshev ◽  
Talgat A. Yensepbayev ◽  
Rizahan U. Uzbekgaliyev ◽  
...  
Keyword(s):  
Phase Formation ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Solid Phase ◽  
Image Data ◽  
Formation Processes ◽  
Ceramic Structure ◽  
Current Voltage ◽  
Average Grain Size ◽  
Temperature Dependences

The article is dedicated to the study of the phase formation processes in Li2ZrO3 ceramics obtained by the method of solid phase synthesis. Interest in these types of ceramics is due to their great potential for use as blanket materials in thermonuclear reactors, as well as being one of the candidates for tritium breeder materials. Analysis of the morphological features of the synthesized ceramics depending on the annealing temperature showed that the average grain size is 90–110 nm; meanwhile the degree of homogeneity is more than 90% according to electronic image data processing results. The temperature dependences of changes in the structural and conducting characteristics, as well as the phase transformation dynamics, have been established. It has been determined that a change in the phase composition by displacing the impurity LiO and ZrO2 phases results in the compaction of ceramics, as well as a decrease in their porosity. These structural changes are due to the displacement of LiO and ZrO2 impurity phases from the ceramic structure and their transformation into the Li2ZrO3 phase. During research, the following phase transformations that directly depend on the annealing temperature were established: LiO/ZrO2/Li2ZrO3 → LiO/Li2ZrO3 → Li2ZrO3. During analysis of the obtained current-voltage characteristics, depending on the annealing temperature, it was discovered that the formation of the Li2ZrO3 ordered phase in the structure results in a rise in resistance by three orders of magnitude, which indicates the dielectric nature of the ceramics.

Nanostructure Formation in Austenitic Stainless Steel

2008 ◽  
Vol 140 ◽  
pp. 173-178 ◽  
Author(s):  
Agnieszka T. Krawczynska ◽  
Małgorzata Lewandowska ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Stainless Steels ◽  
Structural Changes ◽  
Annealing Temperature ◽  
True Strain ◽  
Nano Structure ◽  
Uniform Microstructure ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Nano Grains

Samples of 316LVM stainless steels were hydrostatically extruded in a multi-step process to a total true strain of 1,84 and subsequently annealed at different temperatures. The structural changes occurring as a result of HE and annealing were observed using a transmission electron microscope. The microhardness of the samples was measured using a load of 200g. The results show that hydrostatic extrusion results in a uniform microstructure characterized by a high density of nano-twins. Subsequent annealing at 600°C produces a partial transformation to a nano structure of average grain size 54 nm. At an annealing temperature of 700°C a fullyrecrystallized uniform microstructure consisting of 68 nm diameter nano-grains was formed. It should be noted that 700°C is much lower than that required to recrystallize a micro-grained alloy of the same composition. The microstructural changes which occurred during annealing have a significant effect on the mechanical properties. The microhardness after HE increased following annealing at 500°C. However, annealing at 800°C resulted in a drop in microhardness, indicating the occurrence of grain growth.

Phase formation processes and structural changes in chromite-periclase refractories used during nickel production

2012 ◽  
Vol 52 (5) ◽  
pp. 363-376 ◽  
Author(s):  
T. I. Shchekina ◽  
E. N. Gramenitskii ◽  
A. M. Batanova ◽  
Ya. O. Alfer’eva ◽  
A. A. Sokolov ◽  
...  
Keyword(s):  
Phase Formation ◽  
Structural Changes ◽  
Formation Processes ◽  
Nickel Production

Solid-Phase Crystallization of Amorphous Si0.7Ge0.3/Si and Si/Si0.7Ge0.3 Bilayer Films on SiO2

1996 ◽  
Vol 424 ◽  
Author(s):  
Tae-Hoon Kim ◽  
Myung-Kwan Ryu ◽  
Jin-Won Kim ◽  
Chang-Soo Kim ◽  
Ki-Bum Kim
Keyword(s):  
Annealing Temperature ◽  
Defect Density ◽  
Solid Phase ◽  
Crystallization Rate ◽  
Grain Morphology ◽  
Solid Phase Crystallization ◽  
Bilayer Films ◽  
Average Grain Size ◽  
Average Size ◽  
Equiaxed Grains

AbstractWe have investigated the solid phase crystallization of a-(Si/Si0.7Ge0.3) and a-(Si0.7Ge0.3/Si) bilayer films deposited on SiO2 for an annealing temperature of 550 °C. It was found that, in case of a-(Si0.7Ge0 3/Si), nucleation of crystalline phases occurred at the free surface, while in a-(Si/Si0.7Ge0.3) crystalline phase nucleated at Si0.7Ge0.3/SiO2 interface. The crystallization rate of an a-(Si0.7Ge0.3/Si) is much slower than that of an a-(Si/Si0.7Ge0.3) films. After full crystallization, poly-(Si0.7Ge0.3/Si) has many equiaxed grains and the defect density of the upper Si0.7Ge0.3 was much lower than that of lower Si0.7 Ge0.3 in a poly-(Si/Si0.7Ge0.3) film whose grain morphology was elliptical. The average grain size of poly-(Si0.7Ge0.3/Si) was ˜7 μm and this film had strong (111) preferential orientation, while poly-(Si/Si0.7Ge0.3) had weak (311) or random oriented grains with the average size of˜0.3 μm.

scholarly journals Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1097
Author(s):  
Luran Zhang ◽  
Xinchen Du ◽  
Hongjie Lu ◽  
Dandan Gao ◽  
Huan Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Annealing Temperature ◽  
Reduction Method ◽  
Solid Phase ◽  
Average Particle Size ◽  
Fept Nanoparticles ◽  
Average Particle ◽  
Phase Reduction ◽  
Different Temperatures ◽  
One Step

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

Structural Changes of UHV Deposited Titanium Thin Films in Presence of Oxygen Flow and Temperature

2011 ◽  
Vol 110-116 ◽  
pp. 1094-1098
Author(s):  
Haleh Kangarlou ◽  
Mehdi Bahrami Gharahasanloo ◽  
Akbar Abdi Saray ◽  
Reza Mohammadi Gharabagh
Keyword(s):  
Room Temperature ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Annealing Process ◽  
Oxygen Flow ◽  
Glass Substrates ◽  
Annealing Temperatures ◽  
Titanium Thin Films ◽  
Deposition Angle ◽  
Ti Films

Ti films of same thickness, and near normal deposition angle, and same deposition rate were deposited on glass substrates, at room temperature, under UHV conditions. Different annealing temperatures as 393K, 493K and 593K with uniform 8 cm3/sec, oxygen flow, were used for producing titanium oxide layers. Their nanostructures were determined by AFM and XRD methods. Roughness of the films changed due to annealing process. The gettering property of Ti and annealing temperature can play an important role in the nanostructure of the films.

Grain Boundary Atomic Structures in SrTiO3 and BaTiO3

2007 ◽  
Vol 558-559 ◽  
pp. 851-856 ◽  
Author(s):  
Takahisa Yamamoto ◽  
Teruyasu Mizoguchi ◽  
S.Y. Choi ◽  
Yukio Sato ◽  
Naoya Shibata ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Annealing Temperature ◽  
Unit Length ◽  
Rate Dependency ◽  
Atomic Structures ◽  
Current Voltage ◽  
Single Grain ◽  
Current Voltage Characteristics ◽  
Theoretical Results

SrTiO3 bicrystals with various types of grain boundaries were prepared by joining two single crystals at high temperature. By using the bicrystals, we examined their current-voltage characteristics across single grain boundaries from a viewpoint of point defect segregation in the vicinity of the grain boundaries. Current-voltage property in SrTiO3 bicrystals was confirmed to show a cooling rate dependency from annealing temperature, indicating that cation vacancies accumulate due to grain boundary oxidation. The theoretical results obtained by ab-initio calculation clearly showed that the formation energy of Sr vacancies is the lowest comparing with Ti and O vacancies in oxidized atomosphere. The formation of a double Schottky barrier (DSB) in n-type SrTiO3 is considered to be closely related to the accumulation of the charged Sr vacancies. Meanwhile, by using three types of low angle boundaries, the excess charges related to one grain boundary dislocation par unit length was estimated. In this study, we summarized our results obtained in our group.

pH Influences on Optical Absorption of Anthocyanin from Black Rice as Sensitizer for Dye Sensitized Solar Cell TiO2 Nanoparticles

2016 ◽  
Vol 864 ◽  
pp. 154-158
Author(s):  
Mariya Al Qibtiya ◽  
Eka Cahya Prima ◽  
Brian Yuliarto ◽  
Suyatman
Keyword(s):  
Solar Cell ◽  
Optical Absorption ◽  
Dye Sensitized Solar Cell ◽  
Black Rice ◽  
X Ray ◽  
Dye Sensitized ◽  
Current Voltage ◽  
Average Grain Size ◽  
Uv Visible

Natural dyes extracted from black rice are used as sensitizer for dye sensitized solar cell. The anthocyanin extracted with various pH in acidic and neutral coditions. Preparation of fotolectrode TiO2 film using doctor blade method and resulting average grain size 33,9 nm using X-Ray Diffractometer. Characterization of morphology and cross-section film TiO2 is confirmed by Scanning Electron microscopy (SEM). Optical absorption using UV-Visible Spectroscopy to obtain spectrum absorbance of anthocyanin in various pH. The current-voltage (J-V) characterization shows the performance DSSC have a match relation to the optical absorption. The best absorption of anthocyanin obtained at pH 6 as well as conversion efficiency reaches 2.26% at this pH condition.

Optical Waveguide Formation by Ion Implantation of Ti or Ag

1988 ◽  
Vol 100 ◽  
Author(s):  
D. B. Poker ◽  
D. K. Thomas
Keyword(s):  
Ion Implantation ◽  
Concentration Profile ◽  
Optical Waveguides ◽  
Annealing Temperature ◽  
Solid Phase ◽  
Effective Means ◽  
Complete Removal ◽  
Solid Phase Epitaxy ◽  
Annealing Temperatures ◽  
Residual Damage

ABSTRACTIon implantation of Ti into LINbO3 has been shown to be an effective means of producing optical waveguides, while maintaining better control over the resulting concentration profile of the dopant than can be achieved by in-diffusion. While undoped, amorphous LiNbO3 can be regrown by solid-phase epitaxy at 400°C with a regrowth velocity of 250 Å/min, the higher concentrations of Ti required to form a waveguide (∼10%) slow the regrowth considerably, so that temperatures approaching 800°C are used. Complete removal of residual damage requires annealing temperatures of 1000°C, not significantly lower than those used with in-diffusion. Solid phase epitaxy of Agimplanted LiNbO3, however, occurs at much lower temperatures. The regrowth is completed at 400°C, and annealing of all residual damage occurs at or below 800°C. Furthermore, the regrowth rate is independent of Ag concentration up to the highest dose implanted to date, 1 × 1017 Ag/cm2. The usefulness of Ag implantation for the formation of optical waveguides is limited, however, by the higher mobility of Ag at the annealing temperature, compared to Ti.

FREE VOLUME RELATED STRUCTURAL CHANGES IN THE EPOXY POLYMER TGDDM

1994 ◽  
Vol 08 (13) ◽  
pp. 1699-1711 ◽  
Author(s):  
V. RAVINDRACHARY ◽  
R. RAMANI ◽  
C. RANGANATHAIAH ◽  
S. GOPAL
Keyword(s):  
Free Volume ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Epoxy Polymer ◽  
Slow Increase ◽  
Treatment Variation ◽  
Kinetic Relations ◽  
Long Lifetime ◽  
Average Size ◽  
Free Volume Hole

Positron lifetime measurements have been carried out in an amine-cured epoxy polymer TGDDM/DDS/BFE as a function of annealing temperature. The measured spectra are best fitted to three component analysis. From the measured long lifetime component the average size of the free volume holes has been calculated following Nakanishi et al.’s treatment. Variation of lifetime parameters with temperature indicates the preferential trapping of positronium atoms in the regions of increased free volume hole sizes. On the other hand, positrons are being trapped at micro-voids in the ordered regions. The slow increase of free volume upto 170°C may be due to the thermal expansion and we measure 170° C as the Tg for this epoxy. Lifetime data are also used to calculate the trapping rates in the ordered and disordered regions of the epoxy based on Goldanskii’s kinetic relations.

Sign in / Sign up

Export Citation Format

Share Document