Laser Sintering of Greens Compacts of MoSi2

2006 ◽  
Vol 530-531 ◽  
pp. 364-368
Author(s):  
G. de Vasconcelos ◽  
R. Cesar Maia ◽  
Carlos Alberto Alves Cairo ◽  
R. Riva ◽  
N.A.S. Rodrigues ◽  
...  
Keyword(s):  
Cross Section ◽  
Laser Processing ◽  
Single Phase ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heating Source ◽  
Scanning Electron Microcopy ◽  
Conventional Sintering ◽  
Reduced Time

In this study, the results of the feasibility of sintering green compacts of metallic powder of MoSi2 by a CO2 laser beam as the heating source has been investigated. The main advantage of this technique is to promote a dense material in a reduced time when compared to the conventional sintering process. In order to sintering the MoSi2 powder, green compacts of 6mm of diameter and 1.6mm thickness were produced in a steel die in a uniaxial press at 100MPa and after, isostatic pressed at 350MPa. The micrograph of the samples exposed to the laser radiation performed by scanning electron microcopy (SEM) reveal the efficiency of the sintering process and the X-ray diffraction of the powders confirmed the presence of single phase after and before laser processing. The average microhardness of these compacts reached near to 700 Hv0.2 in the cross section to the laser irradiation, indicating the all sintering of the green compact.

Microwave Sintering of YSZ Electrolyte Materials for SOFC

2008 ◽  
Vol 368-372 ◽  
pp. 238-240 ◽  
Author(s):  
Xi Tang Wang ◽  
Girish M. Kale
Keyword(s):  
Microwave Sintering ◽  
X Ray Diffraction ◽  
Final Phase ◽  
X Ray ◽  
Microwave Furnace ◽  
Scanning Electron Microcopy ◽  
Conventional Sintering ◽  
Y2o3 Content ◽  
Ysz Electrolyte ◽  
Considerable Enhancement

Microwave sintering behaviors of four different compositions of YSZ electrolyte materials were investigated. The samples were sintered in 2.45GHz microwave furnace. For comparison, conventional sintering was performed at 1821K.The densities of sintered samples showed considerable enhancement in the densification process under the influence of microwave fields. The samples with lower Y2O3 content are easy to sinter. The influence of the composition and sintering methods on the final phase composition and microstructure were investigated by X-ray diffraction and scanning electron microcopy. Finer and more uniform microstructures were observed in the microwave sintered samples comparing to the conventionally sintered samples.

Electrodeposition of Aluminum on 316L Stainless Steel from Molten Salts Based on Chlorides

2008 ◽  
Vol 373-374 ◽  
pp. 273-276 ◽  
Author(s):  
Yu Jiang Wang ◽  
Xin Xin Ma ◽  
Guang Wei Guo
Keyword(s):  
Stainless Steel ◽  
Cross Section ◽  
Molten Salts ◽  
Single Phase ◽  
316L Stainless Steel ◽  
Aluminum Layer ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Purity Aluminum ◽  
Scanning Electron

The electrodeposition of aluminum on 316L stainless steel from a molten salts based on chloride has been studied. The surface morphology of the aluminum layer has been examined through scanning electron microscope (SEM) and the structure of the aluminum layer has been analyzed by X-ray diffraction (XRD). The thickness of the deposited aluminum layer has been measured by the method of cross-section scan. It has been suggested that a white, smooth, non-porous and a high purity aluminum layer can be obtained on 316L stainless steel from the ternary chloride molten salts (AlCl3 – NaCl - KCl). And the structure of the aluminum layer was single-phase.

Growth and Characterization of (012)- and (001)-Oriented Epitaxial Anatase Thin Films

2006 ◽  
Vol 46 ◽  
pp. 146-151
Author(s):  
Andriy Lotnyk ◽  
Stephan Senz ◽  
Dietrich Hesse
Keyword(s):  
Thin Films ◽  
Cross Section ◽  
Single Phase ◽  
Electron Beam Evaporation ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
X Ray ◽  
Transmission Electron

Single phase TiO2 thin films of anatase structure have been prepared by reactive electron beam evaporation. Epitaxial (012)- and (001)-oriented anatase films were successfully obtained on (110)- and (100)-oriented SrTiO3 substrates, respectively. X-ray diffraction and cross section transmission electron microscopy investigations revealed a good epitaxial quality of the anatase films grown on the SrTiO3 substrates.

Dielectric, multiferroic properties and resistance modulation of Ta-doped Bi0.97Ba0.03FeO3 ceramics

2014 ◽  
Vol 28 (07) ◽  
pp. 1450050 ◽  
Author(s):  
X. Wang ◽  
S. Y. Wang ◽  
W. F. Liu ◽  
F. Guo ◽  
X. J. Xi ◽  
...  
Keyword(s):  
Leakage Current ◽  
Single Phase ◽  
Switching Behavior ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multiferroic Properties ◽  
Rapid Sintering ◽  
Resistance Modulation ◽  
Process Method

Single phase Bi 0.97 Ba 0.03 Fe 1-x Ta x O 3 ceramics with x = 0, 0.01, 0.03, 0.05 were synthesized by modified rapid sintering process method. The formation of rhombohedral perovskite-like structure was confirmed by X-ray diffraction investigation for all the samples. Dielectric and leakage current measurements indicated that the content of the oxygen vacancy in the samples decreased as a function of the substitution of Ta 5+ ions. A distinct threshold switching behavior was observed in the leakage current density. The impedance measurements suggested that the grain effect made a major contribution to the resistance. The changes in dielectric, multiferroic properties and resistance modulation of the Ta 5+ and Ba 2+ co-doped BiFeO 3 ceramics could have a huge potential for material application.

Effect of Al and ZrO2 on Sinterability and Mechanical Properties of B4C

2010 ◽  
Vol 160-162 ◽  
pp. 1494-1497
Author(s):  
Wen Song Lin ◽  
Liang He
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Single Phase ◽  
Sintering Process ◽  
Densification Rate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rich Solution ◽  
In Situ Reactions

Ceramics composites of B4C matrix with 5 wt% Al and various amount of ZrO2 additives were pressureless sintered under vacuum at 2250 °C for 60 min. Density, hardness, flexural strength and microstructure of the specimens were measured and characterized. Densities above 97% theoretical density (TD) were determined in the samples prepared with the addition of 8 wt% ZrO2 and 5 wt% Al, compared to 86% TD for single-phase B4C. X-ray diffraction analysis showed that B2O3 (impurity in B4C) was eliminated and new phases (ZrB2 and B4C1-x) were formed in the sintered samples, suggesting that in situ reactions between B4C/B2O3 and Al/ZrO2 happened during sintering process. It was showed that the elimination of B2O3 and the forming of boron rich solution of B4C1-x significantly improved the sinterability of B4C matrix ceramics, and consequently enhanced the densification rate greatly. The flexural strength and Vickers hardness of the sintered samples with addition of 8 wt% ZrO2 and 5 wt% Aluminum reached the value of 560 MPa and 30.2 GPa respectively, much higher than those of single-phase B4C ceramics.

scholarly journals The effect of sintering temperatures of TiO2(B)-nanotubes on its microstructure

2018 ◽  
Vol 50 (3) ◽  
pp. 291-298
Author(s):  
H. Sutrisno ◽  
E.D. Siswani ◽  
K.S. Budiasih
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Tio2 Nanotubes ◽  
Single Phase ◽  
Anatase Phase ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Xrd Patterns

Titanium dioxide (TiO2)-nanotubes were prepared by a simple technique reflux. The morphologies and microstructures of nanotubes were characterized by high resolution scanning electron microscopy (HRSEM), high resolution transmission electron microscopy (TEM), powder X-ray diffraction (XRD,) energy dispersive X-ray spectroscopy (EDS) and surface area analyzer. The microstructures of TiO2 phases obtained from the sintering process of TiO2-nanotubes for 1 hour at various temperatures from 100 to 1000?C at intervals of 50?C were investigated from the XRD diffractograms. The analyses of morphologies and microstructures from HRSEM and HRTEM images describe the sample as nanotubes. The nanotube is single phase exhibiting TiO2(B) structure. The XRD patterns show that TiO2(B)-nanotubes transform into anatase phase and then become rutile due to increasing sintering temperatures.

Effects of Ion Doping at Different Sites on Electrical Properties of Ferroelectric Bi4Ti3O12 Ceramics

2011 ◽  
Vol 399-401 ◽  
pp. 796-804
Author(s):  
Yun Yi Wu ◽  
Lei Wang ◽  
Zhi Qiang Hua ◽  
Tao Li ◽  
Xue Tao Yuan ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Single Phase ◽  
Hysteresis Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Doping ◽  
Conventional Sintering ◽  
Ferroelectric Hysteresis ◽  
A Site ◽  
Co Doped

Pure, La3+doped at A site, V5+doped at B site, and La3+and V5+co-doped ferroelectric Bi4Ti3O12(BTO), Bi3.25La0.75Ti3O12(BLT), Bi4Ti2.98V0.02O3(BTV) and Bi3.25La0.75Ti2.98V0.02O12(BLTV) were successfully prepared by conventional sintering technique. The structures of the ceramics were investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. X-ray diffraction indicated that assemblages of all sintered ceramics consist of a single phase of Bi4Ti3O12, implying that the A-site La3+and B-site V5+substitutions in this case do not affect the layered structure. Among these ceramics, BLTV ceramic exhibited the best electrical properties. The leakage current density of BLTV ceramic was only 1.3×10-4Acm-2at 40 KVcm-1, two orders of magnitude lower than BTO ceramic. Besides, a saturated ferroelectric hysteresis loops with largest remnant polarization 2Pr of 30.6μC/cm2was observed for this sample. These suggested that the co-doped Bi4Ti3O12ceramic by La3+and V5+at A and B sites showed advantages in application over the pure BTO, doped BLT and BTV ceramic, respectively.

scholarly journals Synthesis of Cu-CNTs nanocomposites via double pressing double sintering method

2018 ◽  
Vol 23 (4) ◽  
pp. 319-334 ◽  
Author(s):  
Marjan Darabi ◽  
Masoud Rajabi
Keyword(s):  
Electrical Conductivity ◽  
Ball Mill ◽  
Bending Strength ◽  
Sintering Process ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Cold Pressed ◽  
Sintering Method

In this research, copper (Cu)-carbon nanotubes (CNTs) nanocomposites were synthesized with different weight percentages of CNTs by double pressing double sintering (DPDS) method as well as conventional sintering method. A planetary ball mill was used to disperse CNTs in Cu matrix. The milled powders were first cold pressed to 450 MPa in a uniaxial stainless-steel die with cylindrical compacts (diameter: 12 mm and height: 5 mm). The effect of CNTs content and the DPDS method on the properties of the nanocomposites were investigated. The microstructure and phase analysis of Cu-CNTs nanocomposite samples were studied by FESEM and X-Ray Diffraction. The electrical conductivity of nanocomposites was measured and compared to both sintering methods. Mechanical properties of Cu-CNTs nanocomposites were characterized using bending strength and micro-hardness measurements. Enhancements of about 32% in bending strength, 31.6% in hardness and 19.5% in electrical conductivity of Cu-1 wt.% CNTs nanocomposite synthesized by DPDS method were observed as compared to Cu-1 wt.% CNTs nanocomposites fabricated under the similar condition by a conventional sintering process.

Freeze-Fracture Replication of Frozen Outer Segments of Rat Retinal Rods

1969 ◽  
Vol 27 ◽  
pp. 392-393
Author(s):  
Thomas S. Leeson ◽  
C. Roland Leeson
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Outer Segment ◽  
Freeze Fracture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Outer Segments ◽  
Retinal Rods ◽  
Temperature Electron ◽  
Freeze Etching

Numerous previous studies of outer segments of retinal receptors have demonstrated a complex internal structure of a series of transversely orientated membranous lamellae, discs, or saccules. In cones, these lamellae probably are invaginations of the covering plasma membrane. In rods, however, they appear to be isolated and separate discs although some authors report interconnections and some continuities with the surface near the base of the outer segment, i.e. toward the inner segment. In some species, variations have been reported, such as longitudinally orientated lamellae and lamellar whorls. In cross section, the discs or saccules show one or more incisures. The saccules probably contain photolabile pigment, with resulting potentials after dipole formation during bleaching of pigment. Continuity between the lamina of rod saccules and extracellular space may be necessary for the detection of dipoles, although such continuity usually is not found by electron microscopy. Particles on the membranes have been found by low angle X-ray diffraction, by low temperature electron microscopy and by freeze-etching techniques.

Raman And Fluorescence Spectra Observed in Laser Microprobe Measurements of Several Compositions in the Ln-Ba-Cu-O System

1990 ◽  
Vol 48 (2) ◽  
pp. 278-279
Author(s):  
Edgar S. Etz ◽  
Thomas D. Schroeder ◽  
Winnie Wong-Ng
Keyword(s):  
Fluorescence Spectra ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Ceramic Powders ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Raman Microprobe ◽  
Methods Of Synthesis ◽  
Compositional Homogeneity ◽  
Processing Techniques

We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.

Sign in / Sign up

Export Citation Format

Share Document