A New Route for the Synthesis of Pure Bi4(SiO4)3 Crystals by Glass Melt-Cooling Method

2014 ◽  
Vol 875-877 ◽  
pp. 313-317 ◽  
Author(s):  
Dang Ni Gao ◽  
Z.J. Li ◽  
H.W. Guo ◽  
X.F. Wang
Keyword(s):  
High Temperature ◽  
Partial Ordering ◽  
Processing Temperature ◽  
X Ray Diffraction ◽  
High Quality ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Cooling Method ◽  
Melt Cooling ◽  
Scanning Electron

Pure eulytite Bi4(SiO4)3crystals were prepared by high temperature melt cooling method using Bi2O3and SiO2as starting materials. In this study, the properties of the samples were characterized by thermo gravimetric (TG),differential scanning calorimeter (DSC), field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results showed that eulytite Bi4(SiO4)3was crystallized when high temperature glass-melt were cooled to 943°C and obvious exothermal peak is shown on the DSC curve; and pure eulytite Bi4(SiO4)3crystals were synthesized by keeping the processing temperature for 8 hours. Bi4(SiO4)3grains grew larger and the amount of vacancy increased along with the extension of holding time, while Bi4(SiO4)3grains still presented a structure of partial ordering. Eulytite Bi4(SiO4)3prepared through melt-cooling method is of high purity and good stability, and can be applied as starting materials of preparation of Bi4(SiO4)3thin film and high quality Bi4(SiO4)3macrocrystal.

Effect of MgO and NH4OH on Formation of 5Mg(OH)2·MgSO4·3H2O Whiskers

2012 ◽  
Vol 512-515 ◽  
pp. 91-94 ◽  
Author(s):  
Ri Yu ◽  
Jae Hwan Pee ◽  
Hyung Tae Kim ◽  
Kyung Ja Kim ◽  
Young Woong Kim ◽  
...  
Keyword(s):  
Molar Ratio ◽  
X Ray Diffraction ◽  
High Quality ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Practical Applications ◽  
Thermo Gravimetric Analyzer ◽  
High Concentrations ◽  
Sulfate Hydrate ◽  
Scanning Electron

The Magnesium hydroxide sulfate hydrate whiskers (5Mg(OH)2.MgSO4.3H2O, abbreviated 513MHSH) have attracted much attention due to its practical applications as filler and reinforcement. However, it is difficult to produce high quality MHSH because plate-like Mg(OH)2 impurities were formed in high concentrations of OH- and interaction between Mg2+ and OH-. In this work, to reduce formation Mg(OH)2, molar ratio ofSuperscript text magnesium oxide (MgO) and magnesium sulfate (MgSO4.7H2O) were controlled. As a result, when low concentration of SO42-, MHSH whiskers co-existed with hexagonal plate Mg(OH)2. The molar ratio of MgSO4.7H2O/MgO was high, uniform MHSH whiskers were formed without Mg(OH)2. In addition, appropriate amount of NH4OH has affected formation of high quality MHSH. Their morphologies and structures were determined by powder X-ray diffraction (XRD) scanning electron microscopy (SEM) and thermo-gravimetric analyzer (TGA)

scholarly journals Microstructure and properties of boronizing layer of Fe-based powder metallurgy compacts prepared by boronizing and sintering simultaneously

2009 ◽  
Vol 41 (2) ◽  
pp. 199-207 ◽  
Author(s):  
X. Dong ◽  
J. Hu ◽  
Z. Huang ◽  
H. Wang ◽  
R. Gao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Wear Resistance ◽  
Wear Testing ◽  
Processing Temperature ◽  
X Ray Diffraction ◽  
Surface Microhardness ◽  
X Ray ◽  
Substrate Hardness ◽  
Scanning Electron

In this study, the boronized layers were formed on the surfaces of specimens with a composition of Fe-2 wt. % Cu-0.4 wt. % C by sintering and boronizing simultaneously, using a pack boronizing method. The processes were performed in the temperature range of 1050 - 1150 oC at a holding time of 4 hours in 97 % N2 and 3 % H2 atmosphere. Scanning electron microscopy examinations showed that the boronized layers formed on the surface of boronized and sintered specimens have a denticular morphology. The thicknesses of the boronized layers varied from 63 to 208 ?m depending on the processing temperature. The structures of the boronized layers were Fe2B and FeB confirmed by X-ray diffraction analysis. The microhardness values of boronized layers ranged from 1360 to 2066 HV0.3 much higher than that of substrate hardness which was about 186 HV0.3. Wear testing results showed that the wear resistance of the boronized and sintered specimens was significantly improved, resulting from increased surface microhardness.

Influence of Mn and Ni on Austenite Stabilization during a High Temperature Q&P Treatment

2021 ◽  
Vol 1016 ◽  
pp. 379-384
Author(s):  
Eider Del Molino ◽  
Teresa Gutierrez ◽  
Mónica Serna-Ruiz ◽  
Maribel Arribas ◽  
Artem Arlazarov
Keyword(s):  
Phase Transformation ◽  
Electron Microscope ◽  
High Temperature ◽  
Retained Austenite ◽  
Nickel Content ◽  
X Ray Diffraction ◽  
Quenching And Partitioning ◽  
X Ray ◽  
Scanning Electron ◽  
P Cycle

The aim of this work was to study the influence of quenching and partitioning temperatures combined with various levels of Mn and Ni contents on the austenite stabilization along the quenching and partitioning (Q&P) cycle. Three steels with 2 wt.%, 4 wt.% and 6 wt.% manganese and one steel with 2 wt.% nickel content were investigated. Phase transformation temperatures and critical cooling rates were obtained experimentally using dilatometer for each alloy. Q&P cycles with different quenching and partitioning temperatures were also done in dilatometer, thus, allowing monitoring of the expansion/contraction during the whole Q&P cycle. Microstructure characterization was performed by means of a Scanning Electron Microscope and X-Ray Diffraction to measure retained austenite content. It was found that, strongly depending on the Q&P conditions, austenite stabilization or decomposition occurs during partitioning and final cooling. In case of high partitioning temperature cycles, austenite reverse transformation was observed. Certain cycles resulted in a very effective austenite stabilization and interesting microstructure.

INVESTIGATION ON HIGH-TEMPERATURE CORROSION BEHAVIOR OF INCONEL 600 UNDER SO2-BEARING GAS AT 650°C

2019 ◽  
Vol 27 (06) ◽  
pp. 1950155
Author(s):  
KWANG-HU JUNG ◽  
SEONG-JONG KIM
Keyword(s):  
Electron Microscope ◽  
Weight Gain ◽  
High Temperature ◽  
Scanning Electron Microscope ◽  
High Temperature Corrosion ◽  
X Ray Diffraction ◽  
Oxide Structure ◽  
X Ray ◽  
Inconel 600 ◽  
Scanning Electron

The corrosion characteristics of Inconel 600 were investigated at 650∘C in air and 76%[Formula: see text]%[Formula: see text]%[Formula: see text]%SO2 gas environment up to 500[Formula: see text]h. Specimens exposed to each condition were characterized by weight gain, scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction. The oxide structure consisting of the thin Cr2O3 layer and Cr2O3 nodules was observed, which increased the weight gain of specimens. In the SO2-bearing gas, it showed a bigger weight gain due to the coarsening of Cr2O3 nodules. Therefore, it was suggested that the sulfur-accelerated coarsening of Cr2O3 nodules at the high temperature.

A Study of Fe-Based Composite Coating Fabricated by the Self-Propagating High Temperature Synthesis

2012 ◽  
Vol 626 ◽  
pp. 138-142
Author(s):  
Saowanee Singsarothai ◽  
Vishnu Rachpech ◽  
Sutham Niyomwas
Keyword(s):  
High Temperature ◽  
Composite Coating ◽  
Steel Substrate ◽  
The Self ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Precursor Powders ◽  
Scanning Electron

The steel substrate was coated by Fe-based composite using self-propagating high-temperature synthesis (SHS) reaction of reactant coating paste. The green paste was prepared by mixing precursor powders of Al, Fe2O3and Al2O3. It was coated on the steel substrate before igniting by oxy-acetylene flame. The effect of coating paste thickness and the additives on the resulted Fe-based composite coating was studied. The composite coating was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) couple with dispersive X-ray (EDS).

A Porous TiO2 Coating with Vermiform Morphology Formed on Ti through Micro-Arc Oxidation

2013 ◽  
Vol 652-654 ◽  
pp. 1818-1821
Author(s):  
Zhen Fei Liu ◽  
Wei Qiang Wang ◽  
Min Qi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Temperature ◽  
Rutile Phase ◽  
Sodium Tetraborate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Porous Titania ◽  
Micro Arc Oxidation ◽  
Scanning Electron

A porous titania (TiO2) coating with vermiform slots was prepared on the Ti substrate through micro-arc oxidation (MAO) treatment using sodium tetraborate as electrolyte. Morphologies and phase structure were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Results show that the rutile phase increases and anatase decreases gradually with increasing MAO time. The electrolyte of sodium tetraborate has significant influence on the formation of vermiform coatings, which determine the corrosive patterning in the first stage during MAO processing. The evolution of vermiform morphology is proposed as followed: some corrosive pores appear on the surface before arcing; afterward, the adjacent micropores in the dense regions link each other due to the high temperature result from continuous arc action; then, the micropores grow up to big pits and combine with each other with increasing MAO treating time; finally, the vermiform morphology forms on the surface of Ti metal.

Effect of Sintering Temperature on Silver-Copper Nanopaste as High Temperature Die Attach Material

2013 ◽  
Vol 795 ◽  
pp. 47-50 ◽  
Author(s):  
Kim Seah Tan ◽  
Kuan Yew Cheong
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Sintering Temperature ◽  
Grain Structure ◽  
Binder System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Copper ◽  
Die Attach ◽  
Scanning Electron

A novel stencil-printable silver-copper (Ag-Cu) nanopaste that serves as an alternative high temperature die attach material was introduced in this study. The nanopaste was made by mixing 50 nm-sized of Ag and Cu particles with an organic binder system. Sintering temperatures, up to 450°C, were used to sinter nanopaste in air and its post sintered properties were investigated. The viscosity of nanopaste was 350,000 cps and it demonstrated a shear thinning behavior. Scanning electron microscope revealed the change of grain structure with the change in the sintering temperature. Formations of Ag97Cu3 and Ag1Cu99 compounds after sintering were confirmed with X-ray diffraction; and the electrical conductivity of the sintered nanopaste was increased with the increase of the sintering temperature. The study concluded 380°C was the optimum sintering temperature to form a well sintered nanopaste.

scholarly journals Preparation of BaZrO3 powders by a spray-drying process

2003 ◽  
Vol 18 (6) ◽  
pp. 1325-1332 ◽  
Author(s):  
B. Robertz ◽  
F. Boschini ◽  
A. Rulmont ◽  
R. Cloots ◽  
I. Vandriessche ◽  
...  
Keyword(s):  
Spray Drying ◽  
Precursor Solution ◽  
Barium Zirconate ◽  
Drying Process ◽  
X Ray Diffraction ◽  
High Quality ◽  
Corrosion Resistant ◽  
X Ray ◽  
Potential Use ◽  
Scanning Electron

The potential use of barium zirconate for the manufacture of corrosion-resistant substrates emphasizes the need for a simple, inexpensive, and easily scalable process to produce high-quality powders with well-controlled composition and properties. However, the classical solid-state preparation of barium zirconate leads to an inhomogeneous powder unsuitable for applications in highly corrosive environment. For this paper, the possibility to use the spray-drying technique for the preparation of BaZrO3 powders with a controlled size distribution and morphology was investigated. The influence of the nature and concentration of the precursor solution and the influence of the spray-drying step are discussed on the basis of x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and dilatometric measurements.

Biomorphic TiO2 Ceramics Prepared from Cotton Stalk

2012 ◽  
Vol 602-604 ◽  
pp. 526-529
Author(s):  
Qing Wang ◽  
Lin Zhang ◽  
Ya Hui Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
High Temperature ◽  
Sol Gel ◽  
Cotton Stalk ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Template ◽  
Scanning Electron

Biomorphic TiO2 was prepared by high temperature pyrolysis and a modified sol-gel route. The morphology and microstructure of TiO2 samples were characterized by scanning electron microscopy. The phase composition of the resulting sample was analyzed by X-ray diffraction. The results suggest that the biomorphic TiO2 mainly consists of rutile TiO2, and replicates the shape and part microstructure of the carbon template.

Synthesis of Novel Carbon Spheres and Study on Graphitization Process

2013 ◽  
Vol 634-638 ◽  
pp. 2293-2296
Author(s):  
Ai Li Ma ◽  
Cheng Qian Li ◽  
Wu Qing Du ◽  
Jie Chang
Keyword(s):  
High Temperature ◽  
Microwave Plasma ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Carbon Spheres ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cvd Method ◽  
Graphitization Degree ◽  
Scanning Electron

In this paper, carbon spheres were synthesized by CVD method. These carbon spheres exhibit diameters of about 200 nm. Thermal gravimetric analysis indicated the good stability in high temperature of the carbon spheres. The products were treated by microwave plasma and high temperature vacuum heat treatments respectively. The products were characterized by X-ray diffraction, Raman spectroscopy and Field Emission Scanning Electron Microscope. The study indicated that the original products, with perfect morphology and low graphitization degree, were converted to crystal. The different techniques were considered for the influence on the graphitization degree.

Sign in / Sign up

Export Citation Format

Share Document