Texturing of Si3N4 Ceramics via Strong Magnetic Field Alignment

2008 ◽  
Vol 368-372 ◽  
pp. 871-874 ◽  
Author(s):  
Xin Wen Zhu ◽  
Tohru Suzuki ◽  
Tetsuo Uchikoshi ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Strong Magnetic Field ◽  
Slip Casting ◽  
Rotating Magnetic Field ◽  
Pressureless Sintering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Scanning Electron

This paper reports the texture development in Si3N4 by strong magnetic field alignment (SMFA), using slip casting of α-Si3N4 raw powder (SN-E10) and pressureless sintering. The texture of β-Si3N4 in the green and sintered bodies was characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The a, b-axis and c-axis aligned β-Si3N4 has been obtained by the static and rotating magnetic field of 12 T, respectively. The β-seed addition and prolonged sintering both enhance the texture, but the former is more efficient. This work suggests an efficient SMFA strategy of producing highly textured β-Si3N4, particularly the unidirectionally c-axis aligned β-Si3N4 by seeding the α-raw powder using the less-agglomerated β-phase particles.

Microstructure and Properties of Nanosemicrystalline Si3N4 Ceramics with Doped Sintering Additives: Part II. Phase Transformation and Microstructural Control

1998 ◽  
Vol 13 (9) ◽  
pp. 2588-2596 ◽  
Author(s):  
K. H. Ryu ◽  
J-M. Yang
Keyword(s):  
Electron Microscopy ◽  
Pressureless Sintering ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Additives ◽  
Different Temperatures ◽  
Si3n4 Ceramics ◽  
Scanning Electron ◽  
Microstructural Control

The low temperature pressureless sintering of a nanosized Si3N4 powder with doped sintering additives was investigated. The microstructural evolution during sintering at different temperatures was analyzed using x-ray diffraction and scanning electron microscopy. The effect of using nanosized Si3N4 powder as a catalyst to accelerate the α→β–Si3N4 transformation of a commercial Si3N4 powder with larger particle sizes was also investigated. Finally, two stage sintering was used to study the feasibility of controlling the microstructure and the mechanical properties of the nanosized silicon nitride.

Characterization of Ti-xNb (x = 25 – 35) Alloys in as Melt and Annealed States

2019 ◽  
Vol 946 ◽  
pp. 287-292
Author(s):  
Alexander Thoemmes ◽  
Ivan V. Ivanov ◽  
Alexey Ruktuev
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Nb Content ◽  
Scanning Electron

The effect of Nb content on microstructure, mechanical properties and phase formation in as-melt and annealed binary Ti-Nb alloys were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis. The content of Nb varied in the range 25-35 mass % leading to significant changes in the microstructure. The annealed and furnace-cooled binary Ti-Nb samples exhibited HCP martensitic α` phase at a Nb content below 27.5 mass % and metastable BCC β phase at higher contents of Nb. The mechanical properties of alloys depended strongly on the Nb content and type of the dominating phase.

Comparison of Mechanical Properties and Microstructure of Annealed and Quenched Ti-Nb Alloys

2018 ◽  
Vol 769 ◽  
pp. 29-34 ◽  
Author(s):  
Alexander Thoemmes ◽  
Ivan V. Ivanov ◽  
Adelya A. Kashimbetova
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Α Phase ◽  
Nb Content ◽  
Scanning Electron

The effect of Nb content on microstructure, mechanical properties and phase formation in annealed and quenched binary Ti-Nb alloys were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis. The content of Nb varied in the range 0-37 mass % leading to significant changes in the microstructure. The annealed and furnace-cooled binary Ti-Nb samples exhibited HCP martensitic α` phase at a Nb content below 14 mass % and stable BCC β phase at higher contents of Nb. The structure of the quenched samples changed with increase of Nb content in the following order: coarse primary martensite → fine acicular (α`+α``) martensite → single β phase structure. The mechanical properties of alloys strongly depended on the Nb content and type of the dominating phase.

Synthesize Ti3SiC2 from TiH2 by Pressureless Sintering

2012 ◽  
Vol 512-515 ◽  
pp. 676-680 ◽  
Author(s):  
Liang Li ◽  
Ai Guo Zhou ◽  
Li Bo Wang ◽  
Fei Xiang Hu
Keyword(s):  
Electron Microscopy ◽  
Single Phase ◽  
Argon Atmosphere ◽  
Pressureless Sintering ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
Titanium Silicon Carbide ◽  
X Ray ◽  
Titanium Silicon ◽  
Scanning Electron

In this paper, titanium silicon carbide (Ti3SiC2) powders were synthesized from TiH2 as Ti source by pressureless sintering in flowing argon atmosphere without preliminary dehydrogenation. Starting materials are powder mixtures with the mole ratio of 3TiH2/Si/2C or 3TiH2/SiC/C. Both kinds of starting materials were sintered in a tube furnace at the temperature range from 1300°C to 1500°C for 10~180min in flowing argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the phase compositions and morphology of the products after different treatments. It was showed that almost single phase Ti3SiC2 powder (94.7 wt.%) can be synthesized by pressureless sintering from 3TiH2/Si/2C powders at 1400~1425°C for about 180min or from 3TiH2/SiC/C powders at 1425~1500°C for about 180min. From SEM micrographs, as-synthesized samples were porous. Most plate-like grains were about 5~10 μm in diameter and 1~2 μm in thickness. The speed of temperature increasing is an important factor to affect the purity of as-synthesized Ti3SiC2.

Electrocatalytically Active Ni - Re Binary Alloys Electrodeposited with Superimposed Magnetic Field

2012 ◽  
Vol 57 (2) ◽  
pp. 495-501 ◽  
Author(s):  
P. Żabiński ◽  
A. Franczak ◽  
R. Kowalik
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Binary Alloys ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Ammonium Perrhenate ◽  
Scanning Electron ◽  
Citrate Anion

Electrocatalytically Active Ni - Re Binary Alloys Electrodeposited with Superimposed Magnetic FieldThe aim of this work was to obtain Ni-Re binary alloy by a simple method of electrodeposition. Nickel - rhenium alloys have been deposited from nickel sulfamate and ammonium perrhenate electrolyte with citrate-anion additives. The effect of magnetic field superimposed during electrodeposition was studied. The impacts of that parameter on hydrogen evolution process for obtained Ni-Re alloys were examined. The deposited layers were determined by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF).

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.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

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