scholarly journals Influence of Al on Evolution of the Inclusions in Ti-Bearing Steel with Ca Treatment

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 104 ◽  
Author(s):  
Yandong Li ◽  
Tongsheng Zhang ◽  
Huamei Duan
Keyword(s):  
Bearing Steel ◽  
Chemical Compositions ◽  
Calcium Treatment ◽  
X Ray ◽  
Inclusion Formation ◽  
Liquid Phases ◽  
Before And After ◽  
Equilibrium Calculations ◽  
Good Agreement ◽  
Thermodynamic Equilibrium Calculations

Experimental simulations of steelmaking with different amounts of aluminum were achieved in the tube furnace at 1873 K and field scanning electron microscopy and energy dispersive X-ray spectroscopy (FE-SEM and EDX) were employed to explore the characteristics of the inclusions in Ti-bearing steel during the calcium treatment process. It was found that morphologies, chemical compositions, and the size distribution of the inclusions were obviously different before and after calcium treatment. The calcium addition need be carefully considered regarding the mass fraction of aluminum with the purpose of modifying the solid inclusions to liquid phases. The thermodynamic analysis of inclusion formation in the Al–Ti–Ca–O system at 1873 K was conducted, as well as transformation behaviors of inclusions including all types of solid inclusions and liquid phases during solidification. The thermodynamic equilibrium calculations are in good agreement with experimental data, which can be used to estimate inclusion formation in Ti-bearing steel.

scholarly journals Influence of Mercerization on Micro-structure and Properties of Kapok Blended Yarns with Different Blending Ratios

2011 ◽  
Vol 6 (3) ◽  
pp. 155892501100600 ◽  
Author(s):  
Jie Liu ◽  
Fumei Wang
Keyword(s):  
Alkali Treatment ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Cellulose I ◽  
Micro Structure ◽  
Obvious Effect ◽  
Kapok Fiber ◽  
X Ray ◽  
Before And After ◽  
Mercerization Treatment

To investigate the effect of mercerization on micro-structure and the properties of kapok/cotton blended yarns. FTIR spectra and x-ray diffraction (XRD) results, moisture regains and mechanical properties of blended yarns were compared before and after mercerization. The results show that mercerization treatment did not have an obvious effect on chemical compositions of cellulose, but did lead to decreasing on crystallinity of blended yarns, and transformed certain portion of cellulose I into cellulose II. When the NaOH concentration increased from 180g/L to 250 g/L, the strengths of blended yarns increased and elongations at breaking declined, and the extent of changes were lessened gradually with the increase of kapok fiber content, when the NaOH concentration further reached 280g/L, the strengths of blended yarns with high content of kapok fiber dropped dramatically, and elongations at breaking increased gradually, while hygroscopicities of blended yarns increased significantly. Different from cotton fiber, a more moderate alkali treatment condition should be chosen in mercerization process for kapok fiber.

Nickel-containing montmorillonites and chlorites from Brazil, with remarks on schuchardtite

1975 ◽  
Vol 40 (310) ◽  
pp. 141-152 ◽  
Author(s):  
G. W. Brindley ◽  
Jefferson V. De Souza
Keyword(s):  
Structural Formula ◽  
Layer Charge ◽  
Basal Spacing ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Octahedral Sheet ◽  
X Ray ◽  
Crystalline Forms ◽  
Polytype Structure ◽  
Good Agreement

SummaryClay-like, hydrous nickel silicates from Niquelandia, Goias, Brazil, and from Jacupiranga, São Paulo, Brazil, arc examined by X-ray diffraction, chemical analysis, and thermogravimetric methods. The nickel silicates from Niquelandia are ferric iron montmorillonites, with nickel in the octahedral positions and, to a lesser extent, in interlayer positions. The chemical compositions of samples dried at 110°C average (Mg0.15Ni0.08Ca0.015Na0.005) (Fe0.92IIIFe0.025IIAl0.55Mg0.37Ni0.22) (Si3.88Al0.12)O10(OH)2(H2O)0.93. The layer charge originates largely in the octahedral sheet. The cation-exchange capacities average 107 me/100 g clay (110°C). These minerals differ from non-tronites, in which the layer charge originates mainly in the tetrahedral sheets.The nickel silicates from Jacupiranga resemble chlorites, with a non-expanding basal spacing of 14·2-14·3 Å. The better crystalline forms give X-ray data in good agreement with a la polytype structure, which is consistent with their formation by low-temperature processes. Chemical formulae derived on the basis of O10(OH)8 give an average of 5·47 cations in octahedral positions. Thermogravimetric measurements show up to 4% H2O lost between 110 and 500 °C. These results suggest a partial vermiculitization of the interlayer sheets. A new method of calculating a structural formula is developed that gives an interlayer composition of the form R1.75(OH)3.75(H2O)1.14, with (OH + H2O)/R = 2·80, which approaches the ratio for a dioctahedral sheet structure.A comparison of these defect chlorites with available data on schuchardtites shows many similarities; however, schuchardtite is not yet sufficiently well denned for the Jacupiranga chlorites to be given this name.

Growth Kinetics and Polytype Stability in Halide Chemical Vapor Deposition of SiC

2006 ◽  
Vol 527-529 ◽  
pp. 27-30 ◽  
Author(s):  
Saurav Nigam ◽  
Hun Jae Chung ◽  
Sung Wook Huh ◽  
J.R. Grim ◽  
A.Y. Polyakov ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Growth Rates ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Supply ◽  
Equilibrium Calculations ◽  
Thermodynamic Equilibrium Calculations

Growth rates and relative stability of 6H- and 4H-SiC have been studied as a function of growth conditions during Halide Chemical Vapor Deposition (HCVD) process using silicon tetrachloride, propane and hydrogen as reactants. The growth temperature ranged from 2000 to 2150 oC. Silicon carbide crystals were deposited at growth rates in the 100-300 μm/hr range in both silicon- and carbon-supply limited regimes by adjusting flows of all three reactants. High resolution x-ray diffraction measurements show that the growth on Si-face of 6H- and C-face of 4H-SiC substrates resulted in single crystal 6H- and 4H-SiC polytype, respectively. The growth rate results have been interpreted using thermodynamic equilibrium calculations.

scholarly journals Spectroscopic studies of kaolin from different Brazilian regions

Clay Minerals ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 129-135 ◽  
Author(s):  
R. B. Scorzelli ◽  
L. C. Bertolino ◽  
A. B. Luz ◽  
M. Duttine ◽  
F. A. N. G. Silva ◽  
...  
Keyword(s):  
Paper Industry ◽  
Spectroscopic Studies ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Treatments ◽  
Fe Oxides ◽  
Spin Resonance ◽  
Before And After ◽  
Mineralogical Phase

AbstractOver the past several decades, kaolin has been used intensively in the paper industry as a coating and filler material. These applications require kaolin of a high brightness grade, which depends heavily on the level of impurities (mainly Fe-bearing minerals such as Fe oxides and hydroxides) and may be improved by beneficiation processes involving grain-size classification, magnetic separation and chemical treatments. This investigation was carried out on five Brazilian kaolin samples of different geographical and geological origins. Granulometric, mineralogical, chemical and physical characterizations were performed on all samples before and after the beneficiation process.Chemical compositions were determined by X-ray fluorescence and the most important crystalline phases were identified using X-ray diffraction. Kaolinite is the dominant mineralogical phase with minor amounts of muscovite and quartz. The nature of Fe impurities was investigated by electron spin resonance and 57Fe Mössbauer spectroscopy. For all studied kaolin samples, Fe ions (Fe3+ and Fe2+) are present in variable amounts, in the kaolinite structure and also in Fe oxides (magnetite, hematite and goethite). The beneficiation procedure aims to remove these Fe oxides and was found to be most efficient for the Mogi das Cruzes kaolin. The Seridó kaolin had the best whiteness index observed among the analysed samples.

scholarly journals Investigation of the Tribological and Tribochemical Interactions of Different Ferrous Layers Applied to Nitride Surfaces

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Thawhid Khan ◽  
Yukio Tamura ◽  
Hiroshi Yamamoto ◽  
Ardian Morina ◽  
Anne Neville
Keyword(s):  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Tribological Behavior ◽  
Industrial Process ◽  
Chemical Compositions ◽  
Wear Performance ◽  
X Ray ◽  
Before And After ◽  
And Performance ◽  
Micro Analysis

Abstract Nitriding is a widely used industrial process aiming to improve the tribological properties and performance of components. Previous studies have shown the effectiveness of the treatment with friction and wear performance, but very few have focused on the influence of different ferrous layers formed by variant nitriding treatments on tribological and tribochemical behavior. The influence of an oxide (Fe3O4) and sulfide (FeS) layer on friction and wear performance alongside tribochemical formation was investigated when using a fully formulated hydraulic lubricant. The tribological behavior of the variant nitride samples was analyzed using a tribometer and surface profiler. Scanning electron microscope, energy-dispersive X-ray (EDX) spectroscopy, electron probe micro analysis (EPMA), and X-ray photoelectron spectroscopy (XPS) were employed to identify the morphologies and chemical compositions of the treated surface before and after testing. No real effect on friction or wear was observed with the presence of an oxide (Fe3O4) layer, even though the formation of FeS2 was observed within the tribofilm. However, the formation of a sulfide (FeS) layer after sulfur nitriding produced the lowest friction and wear in comparison to the alternative nitride variants. This was due to the lubrication properties of the FeS layer. The study effectively demonstrated that the type of the ferrous layer could impact tribological and tribochemical properties of nitride samples.

Effect of Boron on Diffusion Barrier Characteristics of Pecvd W-B-N Films

1998 ◽  
Vol 514 ◽  
Author(s):  
Dong Joon Kim ◽  
Yong Tae Kim ◽  
Jong-Wan Park
Keyword(s):  
Phase Transition ◽  
Amorphous State ◽  
Annealing Process ◽  
Chemical Compositions ◽  
N Addition ◽  
Flow Ratio ◽  
Excellent Thermal Stability ◽  
X Ray ◽  
Barrier Performance ◽  
Before And After

ABSTRACTThe effects of B and N addition on the phase transition and barrier performance of the plasma deposited W-B-N films are investigated. The W-B-N films have chemical compositions in the range from W67N33 to W38B42N20 corresponding to the flow ratio of B10H14/NH3. Among the films of various compositions of B and N, W46B25N29 film shows excellent thermal stability against the Cu diffusion because the W46B25N29 film keeps the amorphous state even after the annealing at 800°C for 30 min. Resonance backscattering and x-ray photoemission spectra for B and N atoms before and after the annealing process indicate that the amorphous state is retained due to the formation of the B-N bonds.

Estimation of Residual Stress Change due to Cyclic Loading by Classical Elastoplasticity Model and Subloading Surface Model

2016 ◽  
Vol 725 ◽  
pp. 281-286 ◽  
Author(s):  
Ryota Higuchi ◽  
Kazuo Okamura
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Measurement ◽  
Kinematic Hardening ◽  
Bending Test ◽  
Surface Model ◽  
Material Function ◽  
X Ray ◽  
Before And After ◽  
Good Agreement

The subloading surface model has been formulated and applied to the prediction of cyclic loading behavior. The material function prescribing elastic-plastic transition in the original subloading surface model has been extended so as to describe the inverse and reloading behavior and the strain accumulation in cyclic loading more accurately for steel. In the present paper, the extended subloading surface model was applied to the prediction of the change of the residual stress due to cyclic loading. The four-point cyclic bending test was performed for the specimen that had initial residual stress. The distributions of the residual stress before and after cyclic loading were measured by the X-ray stress measurement method. The simulation to the experiment was performed by the extended subloading surface model. The stress distribution after cyclic loading simulated by the extended subloading surface model was in good agreement with measured one, and was more accurate than that by the nonlinear isotropic/kinematic hardening model.

scholarly journals Geochemical and Isotopic Compositions and Geothermometry of Thermal Waters in the Magumsan Area, South Korea

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1774
Author(s):  
Chan-Ho Jeong ◽  
Byeong-Dae Lee ◽  
Jae-Ha Yang ◽  
Keisuke Nagao ◽  
Kyu-Han Kim ◽  
...  
Keyword(s):  
Meteoric Water ◽  
Thermal Waters ◽  
Chemical Compositions ◽  
Radioactive Elements ◽  
Crustal Rocks ◽  
Deep Wells ◽  
Air Mixing ◽  
Δ18o And Δd ◽  
Equilibrium Calculations ◽  
Thermodynamic Equilibrium Calculations

The Magumsan thermal waters of the southeastern Korean Peninsula are pumped out of six deep wells (average depth, 300 m) at temperatures of 30.8–49 °C. The thermal waters are chemically classified into two groups: NaHCO3 type (<31 °C) and NaCl (HCO3, SO4) type (>40 °C), both of which have chemical compositions that are distinct from local groundwater (Ca–HCO3 type). δ18O and δD values suggest that the thermal waters originate from meteoric water and they are isotopically fractionated by silicate hydration or H2S exchange. δ34S values (+7.0 to +15%) of dissolved sulfate in the thermal waters reflect enrichment in 34S through kinetically controlled oxidation of magmatic pyrite in the thermal aquifer and mixing with paleo-seawater. On the 3He/4He vs. 4He/20Ne diagram, the thermal waters plot along a single air mixing line of dominant crustal He, which indicates that the heat source for the thermal waters is non-volcanogenic thermal energy that is generated from the decay of radioactive elements in crustal rocks. Chalcedony geothermometry and thermodynamic equilibrium calculations using the PHREEQC program indicate a reservoir temperature for the immature thermal waters of 54–86 °C and 55–83 °C, respectively.

scholarly journals Avoiding or Promoting Graphite in Carbon-Rich Chromium-Containing CoNiFer Cast Alloys—Part 2: Microstructures of the Elaborated Alloys

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Ophélie Hestin ◽  
Elise Souaillat ◽  
Ahmed Dia ◽  
Moussa Ba ◽  
Patrice Berthod
Keyword(s):  
Ternary Alloys ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Graphite Phase ◽  
X Ray ◽  
Microscopy Image ◽  
Cast Alloys ◽  
The Mean ◽  
Microscopy Image Analysis ◽  
Good Agreement

Nine M-xCr-yC ternary alloys, three cobalt based, three nickel based and three iron based, were elaborated by foundry, from chemical compositions previously selected by the mean of thermodynamic calculations. They were metallographically characterized, using electron microscopy, image analysis, and X-ray diffraction. The as-cast microstructures are in rather good agreement with the ones predicted at 500 and/or 600°C, despite that the elaboration conditions did not meet any thermodynamic equilibrium criteria. Indeed, the obtained carbides and graphite fractions were close to the calculated ones, and the new chromium contents previously chosen effectively led to the expected microstructure modifications, notably almost total suppression of graphite in the nickel alloys and obtaining large fractions of carbides in the cobalt alloys. This allowed specifying the hardness evolution resulting, for these alloys, from the presence or absence of the soft graphite phase, and from the lowering or the enhancement of the carbides presence.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

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