scholarly journals Temperature-influenced Substitution of Si in Ti3(Si,Al)C2  Solid Solution

2020 ◽  
Author(s):  
Jun JI ◽  
Zirun YANG ◽  
Zhenyu ZHANG ◽  
Dechun LI ◽  
Zhi Wang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Sintering Temperature ◽  
Lattice Parameter ◽  
Chemical Compositions ◽  
X Rays ◽  
Experiment Data ◽  
Substitution Process ◽  
Vegard’S Law ◽  
Different Temperatures ◽  
Scanning Electron

Abstract High-pure Ti3(Si,Al)C2 solid solutions were synthesized in the range of 1473 to 1773K. The microstructures and chemical compositions of all samples were characterized by X-rays diffraction (XRD) and scanning electron microscope (SEM). It was worthy noted that experimentally determined lattice parameter c of Ti3(Si,Al)C2 crystal decreased with the increasing of sintering temperature. The contents of Si and Al elements in solid solution were conducted by Vegard’s Law. Gibbs energy differences (△G) of substitution behaviors of Si at different temperatures were also listed. With the increase of temperature, △G of Eq. Ti3(Si0.75Al0.25)C2+0.25Si→Ti3SiC2+0.25Al were negative and decreased gradually, which means that the transformation from Ti3(Si,Al)C2 to Ti3SiC2 was spontaneous and had a greater tendency in higher temperatures. By analyzing the experiment data, a possible mechanism of the substitution process of Si in various temperatures was determined.

scholarly journals Influence of Various Process Parameters on the Density of Sintered Aluminium Alloys

10.14311/1604 ◽  
2012 ◽  
Vol 52 (4) ◽  
Author(s):  
Mateusz Laska ◽  
Jan Kazior
Keyword(s):  
Sintered Density ◽  
Sintering Temperature ◽  
Compaction Pressure ◽  
Nitrogen Atmosphere ◽  
Chemical Compositions ◽  
Green Density ◽  
Heating And Cooling ◽  
Wide Range ◽  
Different Temperatures ◽  
Metallurgy Industry

This paper presents the results of density measurements carried out on Alumix sintered parts. ECKA Alumix aluminium powders were used because of their wide application in the powder metallurgy industry. The compacts were produced using a wide range of compaction pressures for three different chemical compositions. The compacts were then sintered under a pure dry nitrogen atmosphere at three different temperatures. The heating and cooling rates were the same throughout the entire test. The results showed that the green density increases with compaction pressure, but that sintered density is independent of green density (compaction pressure) for each sintering temperature.

An Approach to the Solid Solution Problem Using a Computerized Identification Technique

1969 ◽  
Vol 13 ◽  
pp. 539-549
Author(s):  
Gerald G. Johnson ◽  
Frank L. Chan
Keyword(s):  
Solid Solution ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Powder Diffraction File ◽  
X Ray ◽  
Complete Solid Solution ◽  
Vegard’S Law ◽  
Identification Technique ◽  
Approximate Composition ◽  
End Members

Since for most real systems, solid solution effects influence the position and intensity of the x-ray powder diffraction pattern, it is desirable and necessary to have an automatic system which will identify standard reference phases regardless of the amount of solid solution. Using the system CdS-ZnS, where the lattice parameter a0 changes from 4.136 to 3.820Å, with complete solid solution over the entire range of composition, an illustrative study was made. This work presents the results obtained from a computer analysis of the powder pattern obtained. It has been found that if the starting chemistry is known and the end members of the series are in the ASTM Powder Diffraction File, that the solid solution can be identified. Once the phases present are identified, a plot following Vegard's law yields the approximate composition of the sample under consideration. These two methods of compositional determination agree quite well. Examples of the computer system and description of the program input and output with interpretation of the results will be discussed.

Effects of Thermal Treatment on the Structure of Eu:YAG Nanopowder

2007 ◽  
Vol 128 ◽  
pp. 107-114 ◽  
Author(s):  
Maria Luisa Saladino ◽  
Eugenio Caponetti ◽  
Stefano Enzo
Keyword(s):  
Thermal Treatment ◽  
Lattice Strain ◽  
Rietveld Method ◽  
Lattice Parameter ◽  
Spherical Particles ◽  
X Rays ◽  
Garnet Phase ◽  
The Matrix ◽  
Different Temperatures ◽  
Co Precipitation

Eu:YAG nanopowder precursors were obtained by co-precipitation of aluminium, yttrium and europium nitrates solution with ammonia. The hydroxides precursors were calcined at different temperatures from 900 to 1200°C as a function of holding time (1, 2 and 6 hours). The presence of Eu3+ ions in the matrix was confirmed by Energy Dispersive X-rays analysis. X-Ray Diffraction investigation by the Rietveld method shows that the sample treated at 900°C for 1 hour is essentially the garnet phase with the minor presence of hexagonal and monoclinic metastable phases. The Eu3+ ions are incorporated into the garnet phase, as is suggested by the lattice parameter value being larger than that in literature data (homogeneous strain). For the sample treated at 900°C for 1 hour, electron microscopy observations showed agglomerates of spherical particles of mean size about 50 nm. At higher temperature treatments and for longer holding times the minority hexagonal and monoclinic phases totally disappeared. However, the lattice parameters of the cubic garnet phase gradually decreased with temperature, suggesting an expulsion of Eu3+ ions from the solid solution. Simultaneous with this, it was noted that the lattice strain reached a maximum value, but to later decrease, due to the vacancies created by the Eu species initially migrating to the surface of the coherent domains of diffraction. The lattice strain definitely decreased upon more drastic thermal treatments. Meanwhile, FEG-SEM and TEM observations on the same samples confirmed the growth of the garnet particles as a function of the thermal treatment.

Morphology of Sintered Cr-Mo Porous Materials

2015 ◽  
Vol 825-826 ◽  
pp. 838-843
Author(s):  
Moritz Boehm ◽  
Thomas Schmoelzer ◽  
Reinhard Simon ◽  
Christian Gierl-Mayer
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Linear Expansion ◽  
Solid Phase ◽  
Phase Region ◽  
Miscibility Gap ◽  
Liquidus Boundary ◽  
Different Temperatures ◽  
Scanning Electron

Chromium and molybdenum exhibit continuous solubility in the solid phase region at temperatures of 908°C and above [1]. At lower temperatures, the system exhibits a miscibility gap. Furthermore a congruent minimum in the liquidus boundary exists at 1854°C. Chromium and molybdenum powders with different particle morphologies were mixed and porous green parts were produced by pressing. Sintering experiments were performed at different temperatures and for different chromium to molybdenum ratios. To investigate the evolution of the microstructure, sintering was interrupted at different temperatures and points in time. The microstructure and morphology of the sintered parts was investigated by scanning electron microscopy as well as light optical microscopy. It was found that during sintering, a Cr-Mo solid solution is formed. Depending on the molybdenum content, this induces either shrinking or swelling of the porous parts. Samples exhibited a linear expansion of up to 10% and final porosities of up to 65%.

Effect of Reaction between Fe and Carbide Particles on Mechanical Properties of Fe-Base Composite

2008 ◽  
Vol 55-57 ◽  
pp. 357-360 ◽  
Author(s):  
S. Chakthin ◽  
Nuchthana Poolthong ◽  
Ruangdaj Tongsri
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Carbide Particle ◽  
Sintering Temperature ◽  
Particle Sizes ◽  
Different Temperatures ◽  
Base Composite ◽  
Sic Composites ◽  
Carbide Particles ◽  
Sic Particle

Sintered Fe-5 wt. % carbide (SiC or TiC) composites have been prepared via a powder metallurgy (P/M) route. Two carbide particle sizes, < 20 µm and 20-32 µm, were mixed with Fe powder. The powder mixtures were compacted and sintered at 3 different temperatures, 1100, 1150 and 1200 °C. Microstructures of sintered Fe-5 wt. % SiC composites showed evidence of SiC decomposition. The decomposed Si and C atoms diffused into Fe particles resulting in formation of solid solution of Si and C in Fe during sintering. During cooling, the solid solution of C in Fe decomposed to pearlite structure (ferrite and cementite (Fe3C) lamellar structure). Microstructures of sintered Fe-5 wt. % TiC composites showed no evidence of TiC decomposition at the investigated sintering temperatures. Because of the reaction between SiC and Fe, tensile strength and hardness of the sintered Fe-SiC composites were higher than those of the sintered Fe. Experimental results showed that strength and hardness of the sintered Fe-SiC composites increased with increasing sintering temperature and with decreasing SiC particle size. In contrast, mechanical properties of the sintered Fe-TiC composites were inferior to those of the sintered Fe. The reason of poor mechanical properties may be attributed to poor bonding between Fe and TiC particles.

Properties and Phase Shift Structure of (1-x)BT-(x)BNT Ceramics

2016 ◽  
Vol 675-676 ◽  
pp. 615-618
Author(s):  
Chompoonuch Warangkanagool
Keyword(s):  
Sintering Temperature ◽  
Sodium Titanate ◽  
Lattice Parameter ◽  
Bismuth Sodium Titanate ◽  
X Ray Diffraction ◽  
Fluid Medium ◽  
X Ray ◽  
Xrd Patterns ◽  
Bismuth Sodium ◽  
Scanning Electron

In the research, the properties of barium titanate - bismuth sodium titanate [(1-x)BaTiO3-(x)Bi0.5Na0.5TiO3: (1-x)BT-(x)BNT] ceramics prepared by conventional mixed oxide method with various molecular weight of BNT or x between 0.0 and 0.3 were investigated. The optimum condition for calcined powders of x = 0.0 was found at 900 °C for 2 h, and x = 0.1 - 0.3 were found at 850 °C for 2h. The calcined powders were pressed and sintered at 1000 – 1200 °C for 2h. The phase structure was examined by x-ray diffraction (XRD). The microstructure was examined by scanning electron microscopy (SEM). Density of sintered samples was measured by Archimedes method with distilled water as the fluid medium. It was found that, all various x of (1-x)BT-(x)BNT ceramics XRD patterns display the tetragonality increased with increasing sintering temperature. All the peaks shift to higher angles when increasing x value indicating the decrease of lattice parameter “a” and increase of lattice parameter “c”. The average grains size of (1-x)BT-(x)BNT ceramics was increased with increasing sintering temperature. The highest density was 5.53 g/cm3 and was obtained from the sample sintered at 1200 °C.

scholarly journals Generalizing the Chiral Self-Assembly of Spheres and Tetrahedra to Non-Spherical and Polydisperse Molecules in (C70)x(C60)(1-x)(SnI4)2

2021 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Solid Solution ◽  
Self Assembly ◽  
Lattice Parameter ◽  
Nonspherical Particles ◽  
High Symmetry ◽  
Chiral Phase ◽  
Cubic Lattice ◽  
Vegard’S Law ◽  
Chiral Materials ◽  
Chiral Crystals

We describe the spontaneous chiral self-assembly of C<sub>70</sub> with SnI<sub>4</sub> as well as a mixture of C<sub>60</sub> and C<sub>70</sub> with SnI<sub>4</sub>. Macroscopic single crystals with the formula (C<sub>70</sub>)<sub>x</sub>(C<sub>60</sub>)<sub>1-x</sub>(SnI<sub>4</sub>)<sub>2</sub> (x = 0-1) are reported. C<sub>60</sub>, which is spherical, and C<sub>70</sub>, which is ellipsoidal, form a solid solution in these crystals, and the cubic lattice parameter of the chiral phase linearly increases as x grows from 0 to 1 in accordance with Vegard’s law. Our results demonstrate that nonspherical particles and polydispersity are not an impediment to the growth of chiral crystals from high-symmetry achiral precursors, providing a route to assemble achiral particles including colloidal nanocrystals and engineered nanostructures into chiral materials without the need to use external templates.<br>

Investigation on the Structural Properties of a New Prepared 0.2PZS-0.8PLZT Ceramics

2013 ◽  
Vol 856 ◽  
pp. 197-200
Author(s):  
Adel Sakri ◽  
Ahmed Boutarfaia
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Smart Materials ◽  
Sintering Temperature ◽  
Human Life ◽  
Advanced Technology ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

View of the importance that has the development in the field of advanced technology transmission in human life, smart materials draws the attention of many researchers. In this contribution, we are interested in synthesizing a new smart material of the ceramic type based on Pb, Zr, Ti (PZT) doped La in the site A, and Sb, Zn in site B from a solid solution of pure oxides. The synthesized samples are thermally treated at 800°C. The techniques of x-ray diffraction (XRD) and SEM (scanning electron microscopy) are used to characterize the microstructure (the crystallographic phase), and the densities of the obtained samples were determined from their weights and volumes. The effect of sintering temperature on the microstructure properties was studied.

Processing and Properties of Niobia-Doped Alumina Sintered at 1400oC

2014 ◽  
Vol 798-799 ◽  
pp. 665-670 ◽  
Author(s):  
Willian Trindade ◽  
Marcelo Henrique Prado da Silva ◽  
Alaelson Vieira Gomes ◽  
José Brant de Campos ◽  
Luis Henrique Leme Louro
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Elastic Constants ◽  
Dwell Time ◽  
Sintering Temperature ◽  
X Rays ◽  
Sintering Additive ◽  
Average Grain Size ◽  
Scanning Electron

Niobia is used as a sintering additive in alumina processing because it lowers the sintering temperature. This work investigated the influence of sintering dwell time at 1400oC on the properties of 4 wt% niobia doped alumina. The sintered ceramics were characterized by scanning electron microscopy (SEM), and X rays diffraction (XRD) with Rietveld refinement. Measurements of density, average grain size, hardness, and elastic constants were also performed. The results showed that the porosity depend on the time sintering and this influence on the elastic properties. Longer sintering times improved densification and with this the Young's Modulus.

scholarly journals Structural properties of CoxCu1−xFe2O4 solid solution**

2021 ◽  
Vol 30 (1) ◽  
pp. 220-227
Author(s):  
Natheer B. Mahmood ◽  
Farqad R. Saeed ◽  
Kadhim R. Gbashi ◽  
Ali Hamodi ◽  
Zahraa M. Jaffar
Keyword(s):  
Solid Solution ◽  
Lattice Parameter ◽  
Peak Position ◽  
Unit Cell ◽  
Factor X ◽  
Ionic Radii ◽  
Peak Intensity ◽  
Vegard’S Law ◽  
Density Of Electrons ◽  
Xrd Patterns

Abstract Crystallography information files (CIF) were designed formed CoxCu1−xFe2O4 solid solution with the substitution factor x=0 to 1 with an increment of 0.1 depending on Vegard's law by using crystallography software. The effect of the substitution factor has been studied on some parameters and properties of the Co-Cu ferrite system, such as the effect of substitution factor on the lattice parameter, the volume of unit cell, and the density of the unit cell. Also, XRD patterns were estimated by crystallography software depending on the mathematical models of XRD. The XRD results showed a slight shift in the peak position varying with the substitution factor, these are due to the change in lattice parameter caused by the substitution of ions with different ionic radii. XRD also showed an increment in peak intensity varying with the substitution factor, that's due to an increase in the concentration of Cu which led to an increase in the density of electrons.

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