Effect of the Dwell Temperature on Spark Plasma Sintered CaCu3Ti4O12

2012 ◽  
Vol 727-728 ◽  
pp. 982-987
Author(s):  
E. de Carvalho ◽  
Marcelo Bertolete ◽  
Izabel Fernanda Machado ◽  
E.N.S. Muccillo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lattice Parameter ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Diffraction Patterns ◽  
Scanning Electron

Polycrystalline CaCu3Ti4O12 ceramics were prepared by solid state reactions by spark plasma sintering (SPS) technique. In this study, the effects of the dwell temperature on structural, microstructural and dielectric properties of CaCu3Ti4O12 ceramics have been investigated. Powder mixtures were calcined at 900°C for 18 h before SPS consolidation. The dwell temperatures were 850, 900, 915 and 930°C. Sintered pellets were characterized by X-ray diffraction, scanning electron microscopy and impedance spectroscopy. X-ray diffraction patterns show evidences of a single-phase perovskite-type structure. The calculated lattice parameter is 7.40 Å. The hydrostatic density increases slightly with increasing dwell temperature. Scanning electron microscopy observations revealed a heterogeneous microstructure for all samples. The dielectric loss remains constant over a wide temperature range. The obtained permittivity is approximately 103 at 1 kHz. The increase of the dwell temperature is found to produce a brittle ceramic.

THE GROWTH OF MnSi1.73 PREPARED BY SPARK PLASMA SINTERING

2004 ◽  
Vol 18 (01) ◽  
pp. 87-93 ◽  
Author(s):  
ZHIMIN WANG ◽  
YIDONG WU ◽  
YUANJIN HE
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spark Plasma Sintering ◽  
X Ray Diffraction ◽  
Mechanical Pressure ◽  
Growth Processes ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

Crystals of MnSi 1.73 were prepared by Spark Plasma Sintering (SPS) technique, analyzed by X-ray diffraction (XRD), and invested by metalogragh and scanning electron microscopy (SEM). The growth processes of the samples were studied. It was found that the Mn–Si powders partly formed MnSi 1.73 crystals at 912–937 K under the mechanical pressure of 20 MPa in low vacuum (about 5.0 Pa), and fully formed MnSi 1.73 crystals after sintered at 1173 K for 15 minutes under 40 MPa.

The Synthesis of Nano-Structured TiO2 Ceramics by Modified Two Step Sintering

2012 ◽  
Vol 500 ◽  
pp. 29-33
Author(s):  
Bao Rang Li ◽  
Xin Ming Xi ◽  
Yang Bai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

The nano-TiO2powders with the average particle size of about 40nm were used as starting materials. The compacted powders were firstly performed in Spark-plasma-sintering (SPS) at a high temperature and then sintered in air for hours at a relatively low temperature. The obtained samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed an obvious reduction in grain size was achieved by taking advantage of modified two step sintering (MTSS). The value of the relative grain growth d/do for the samples prepared by MTSS was less than 3.

Interactions between AlN and SiAlON Ceramics

2008 ◽  
Vol 403 ◽  
pp. 97-98
Author(s):  
A. Kalemtas ◽  
Nurcan Calis Acikbas ◽  
Ferhat Kara ◽  
Hasan Mandal ◽  
Kristoffer Krnel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aspect Ratio ◽  
Reaction Zone ◽  
High Aspect Ratio ◽  
X Ray ◽  
Plasma Sintering ◽  
Reaction Region ◽  
Spark Plasma ◽  
Scanning Electron

In the present study, interactions between AlN and SiAlON laminated couples were investigated after gas pressure (GPS) and spark plasma sintering (SPS) by scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) with the aim to produce laminated composites. In the laminated couples sintered by GPS, a significant reaction zone (~100-150 μm), containing a high aspect ratio of elongated polytypoid grains, was observed at the interface. However, in the case of laminated couples sintered by SPS, a considerably thin reaction region (~2-3 μm) was observed, elongated polytypoid grain formations were also detected.

TiCN-Based Cermets Strengthened with SiC Nano-Whiskers by Spark Plasma Sintering

2012 ◽  
Vol 512-515 ◽  
pp. 932-935
Author(s):  
Ying Peng ◽  
Zhi Jian Peng ◽  
Xiao Yong Ren ◽  
Hui Yong Rong ◽  
Cheng Biao Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Addition Amount ◽  
Scanning Electron

TiCN-based cermets with different amounts of SiC nano-whiskers were prepared by spark plasma sintering. The microstructure and mechanical properties of the as-prepared cermets were investigated. X-ray diffraction revealed that there were no SiC peaks detected, turning out some peaks of new carbide and silicate hard phases. Scanning electron microscopy indicated that there were more and more pores in the cermets with increasing amount of SiC whisker added, and the fracture mechanism of the cermets was mainly inter-granular fracture. With increasing addition amount of nano-SiC whisker, the hardness and flexural strength of the cermets increased first and decreased then, presenting the highest hardness (2170 HV) and flexural strength (750 MPa), respectively, when the addition content of nano-whiskers is 2.5 wt%.

Intergrowth of several solid phases from the Y–Ni–B–C system in a large YNi2B2C crystal

2008 ◽  
Vol 41 (4) ◽  
pp. 738-746 ◽  
Author(s):  
Torsten Weissbach ◽  
Tilmann Leisegang ◽  
Andreas Kreyssig ◽  
Matthias Frontzek ◽  
Jens-Uwe Hoffmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
Orientation Relation ◽  
X Ray ◽  
Polished Cross Section ◽  
Diffraction Patterns ◽  
The Individual ◽  
Microscopy Images ◽  
Scanning Electron

A YNi2B2C single crystal containing traces of foreign phases was inspected by means of neutron and X-ray diffraction as well as scanning electron microscopy and X-ray spectroscopy methods. The diffraction patterns obtained from the experiments look similar to those expected for a superstructure. Nevertheless, they can be interpreted as crystallographically oriented precipitations of YB2C2and Ni2B within the YNi2B2C crystal, formed during the cooling process. The orientation relation between the lattices was obtained from experimental neutron and X-ray data. Structure refinements of the collected X-ray data were performed by separation of the intensity data of the individual phases. Scanning electron microscopy images of the inclusions found on a polished cross section of the crystal are presented; their chemical composition was determined using wavelength-dispersive X-ray analysis.

Microstructure Properties of Bi0.5Na0.5TiO3-BaZrO3 Piezoelectric Ceramics

2012 ◽  
Vol 151 ◽  
pp. 310-313
Author(s):  
Jenn Sen Lin ◽  
Teng Chin Yu ◽  
Cheng Hsing Hsu ◽  
Ci Jie Huang ◽  
His Wen Yang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid State Route ◽  
Diffraction Patterns ◽  
Conventional Solid State Route ◽  
Scanning Electron

The microstructure properties of the perovskite Bi0.5Na0.5TiO3-BaZrO3 ceramics were prepared with the conventional solid-state route have been investigated. The resultant microstructure properties were analyzed based upon the densification, the X-ray diffraction patterns and scanning electron microscopy. The correlation between the microstructures and the sintering temperature was also examined.

scholarly journals Properties of WCCo Composites Produced by the SPS Method Intended for Cutting Tools for Machining of Wood-Based Materials

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2618
Author(s):  
Joanna Wachowicz ◽  
Tomasz Dembiczak ◽  
Grzegorz Stradomski ◽  
Zbigniew Bałaga ◽  
Marcin Dyner ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Primary Particle ◽  
Cutting Tools ◽  
Cobalt Content ◽  
Primary Particle Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

This paper presents the possibility of using the Spark Plasma Sintering (SPS) method to obtain WCCo composite materials. Such materials are used as cutting blades for machining wood-based materials. Two series of composites, different in grain size and cobalt content, were analyzed in the paper. The produced materials were characterized using Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and tribological properties were determined. In addition, preliminary tests were carried out on the durability of the blades made of sintered WCCo composites while machining three-layer chipboard. The results of the microstructure analysis proved that the SPS method makes it possible to obtain solid composites. Phase analysis showed the occurrence of the following phases: WC, Co, and Co3W9C4. The lowest friction coefficient value was found in samples sintered using powder with an average primary particle size of 400 nm (ultrafine).

Microstructure and thermoelectric properties of CuInSe2/In2Se3 compound

2018 ◽  
Vol 32 (03) ◽  
pp. 1850018 ◽  
Author(s):  
Kang Wang ◽  
Jing Feng ◽  
Zhen-Hua Ge ◽  
Peng Qin ◽  
Jie Yu
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Room Temperature ◽  
Solvothermal Method ◽  
Chalcopyrite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Scanning Electron

CuInSe2 powders were synthesized by solvothermal method, and then the CuInSe2/In2Se3 bulk samples were fabricated by spark plasma sintering (SPS) technique. To investigate the phase composition, the powders were determined by X-ray diffraction (XRD). The microstructures of the powders and bulk samples were observed by scanning electron microscopy (SEM). The transportation of the electronic properties and thermal conductivity were measured at room temperature to 700 K. According to the results, the CuInSe2 powders appeared in flower-like patterns which ranged from 3 [Formula: see text]m to 6 [Formula: see text]m. CuInSe2 powders were synthesized at 180[Formula: see text]C with a chalcopyrite structure. The Seebeck coefficient increased significantly in composite thermoelectric materials up to [Formula: see text] at 623 K. The thermal conductivity of the sample significantly decreases from the room temperature to 700 K. The CuInSe2 bulk composite by solvothermal method achieves the highest ZT value of 0.187 at 700 K.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

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