scholarly journals PHASE COMPOSITION OF OXIDE FILMS FORMED ON THE SURFACE OF THE FE-CR-AL SYSTEM COATINGS

2020 ◽  
pp. 14-18
Author(s):  
V. G. Shmorgun ◽  
A. I. Bogdanov ◽  
O. V. Slautin ◽  
V. P. Kulevich
Keyword(s):  
Phase Composition ◽  
Aluminum Content ◽  
Oxide Films ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Glancing Angle ◽  
Stable Growth ◽  
Metastable Alumina

The phase composition of the oxide films on the surface of the Fe-Cr-Al system coatings is studied using glancing angle X-ray diffraction. It is shown that at 900 °С the formed oxide films consist of αAlO and (FeCr)O, to which FeAlO oxide is added during long-term exposure. An increase in temperature to 1100 °C intensifies the growth of oxide films, and an increase in the aluminum content ensures a stable growth of αAlO and FeAlO oxides. When the aluminum content in the coating is more than 10 at. % at large exposure times, metastable alumina δAlO is formed, the formation of which is associated with a decrease in the concentration of chromium in thin surface layers.

scholarly journals A method for accurate texture determination of thin oxide films by glancing-angle laboratory X-ray diffraction

2014 ◽  
Vol 47 (2) ◽  
pp. 575-583 ◽  
Author(s):  
Alistair Garner ◽  
Michael Preuss ◽  
Philipp Frankel
Keyword(s):  
Oxide Films ◽  
X Ray Diffraction ◽  
Aqueous Corrosion ◽  
Texture Measurement ◽  
X Ray ◽  
Peak Broadening ◽  
Glancing Angle ◽  
Thin Oxide Films ◽  
Diffraction Peaks ◽  
Thin Oxide

The present article describes a modification to the standard method of glancing-angle X-ray diffraction for accurate measurement of the texture of thin oxide films. The technique resolves the problems caused by overlapping diffraction peaks originating from multiphase materials with asymmetric unit cells and the peak broadening associated with sample tilt during glancing-angle texture measurement. The entire 2θ range of interest is recorded as a function of sample orientation, and the integrated intensities from different crystallographic planes are extracted from fitted diffraction profiles. The technique allows for pole figures to be plotted from diffraction peaks that could otherwise not be resolved and separates contributions from neighbouring peaks, leading to a more accurate representation of the existing oxide texture. The proposed method has been used for determining texture in a 3 µm layer of monoclinic/tetragonal zirconium oxide grown during aqueous corrosion testing and has been verified by additional synchrotron X-ray diffraction measurements.

Preparation of Chrome Carbide Coatings on T/P 24 by PIRAC

2012 ◽  
Vol 452-453 ◽  
pp. 77-80 ◽  
Author(s):  
Shou Jun Wu ◽  
Gutmanas Elazar
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Power Plants ◽  
Erosion Resistance ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Carbide Coatings ◽  
Short Times ◽  
Scanning Electron

In order to improve oxidation/erosion resistance of the T/P 24 steel components used in advanced power plants, chrome carbide coatings were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) on T/P24 at 700-1000°C. Microstructure and phase composition of the obtained surface layers were characterized employing X-ray diffraction and scanning electron microscopy with chemical analysis (SEM/EDS). Results showed that homogenous smooth chrome carbide coatings can be formed on the substrate. Phase composition of the prepared coatings are differs with PIRAC temperatures. Prepared at lower temperatures or short times treatment, Cr23C6, Cr7C3 and Cr3C2 can be detected in the coatings. While, at higher temperatures or longer treatment times, Cr23C6 is subtotal phase of the produced coating. Moreover, the lower the PIRAC temperature is, the more of Cr7C3 and Cr3C2 are. Thermodynamics calculation based on Gibbs free energy is applied to explain phase composition difference of the coatings.

The Effect of Ce Added to Carburizing Paste on Phase Composition of Carburized Surface Layers

2015 ◽  
Vol 1114 ◽  
pp. 183-189
Author(s):  
Mihai Cojocaru ◽  
Daniela Dragomir ◽  
Leontin Druga ◽  
Victor Kuncser ◽  
Petre Badica
Keyword(s):  
Phase Composition ◽  
Retained Austenite ◽  
Lower Bainite ◽  
Case Depth ◽  
Transfer Mechanism ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
High Affinity ◽  
Carburized Layer

Investigations on carburized layers phase composition are usually made ​​by optical microscopy, electron microscopy and X-ray diffraction. A microstructure consisting in different proportions of superior bainite, inferior bainite, martensite and retained austenite was found after carburizing in paste of the 21NiCrMo2 steel which has appropriate bainitic hardenability. The investigations carried out on 21NiCrMo2 steel samples, carburized in paste with additions of about 10% Ce, highlighted a significant change of phase proportions ratio in the carburized layer resulting in an important increasing of the lower bainite ratio. It was also observed, that the carburized layer case depth obtained in the carburizing paste with Ce additions does not significantly differ in relation to that attained in the carburizing paste without Ce additions but the microhardness increases considerably. The reason is connected also to the presence of Ce carbide identified by X-ray diffraction in the carburized layer. The Ce hard affinity towards oxygen and its influence on bainitic hardenability increasing is well known and adopted, however neither Ce transfer mechanism from carburizing paste to the carburizing layer and nor the effects of its high affinity to oxygen (for example) are not addressed in this particular case. The present study proposes a possible transfer mechanism of Ce in the carburized layer and an explanation of the consequences of Ce hard affinity towards oxygen on the phase composition of the carburized layer. Nanoscale iron oxides such as wüstite, magnetite and maghemite were identified in the surface of the carburized layer by Mössbauer spectrometry.

Surface Properties of the Ta and Ag Dual-Ion-Implanted Ti6Al4V Alloy

2013 ◽  
Vol 738 ◽  
pp. 78-82
Author(s):  
Chong Yan Leng ◽  
Rong Zhou ◽  
Xu Zhang
Keyword(s):  
Phase Composition ◽  
Diffraction Analysis ◽  
Photoelectron Spectroscopy ◽  
Ti6al4v Alloy ◽  
X Ray Diffraction ◽  
Spectroscopy Analysis ◽  
X Ray ◽  
Glancing Angle ◽  
Chemical States ◽  
Ion Implanted

First, Ti6Al4V alloy samples were modified by tantalum ion implantation at a dose of 1.5×1017ions/cm2, and then silver ion at a dose of 1×1017ions/cm2. Glancing angle X-ray diffraction analysis was used to characterize the phase composition of un-implanted Ti6Al4V alloy and Ta+Ag dual-ion-implanted Ti6Al4V alloy samples. X-ray photoelectron spectroscopy analysis was used to investigate the chemical states of the elements on the Ta+Ag dual-ion-implanted Ti6Al4V alloy sample’s surface. The results show that small amounts of Ta and Ag were present in their elementary forms, along with TiO2, Ta2O5, and TaOx.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Formation of nanoscale sodium dodecahydro-closo- dodecaborate Na2[B12H12] on silicate matrix surface

2019 ◽  
Vol 484 (1) ◽  
pp. 41-43
Author(s):  
E. A. Malinina ◽  
V. K. Skachkova ◽  
I. V. Kozerozhets ◽  
V. V. Avdeeva ◽  
L. V. Goeva ◽  
...  
Keyword(s):  
Phase Composition ◽  
Ammonium Salt ◽  
Liquid Glass ◽  
Silicate Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
Salt Sample ◽  
Matrix Surface

The method of nanoscaled sodium dodecahydro-closo-dodecaborate Na2[B12H12] synthesis is presented. The composite is heated to 200°C to yield the desired product, forming with the introduction of triethyl- ammonium salt [Et3NH]2[B12H12] into the silicate matrix of a sodium liquid glass. The morphology and phase composition of the synthesized sample are studied through SEM and X-ray diffraction methods, in comparison to those of a standard salt sample Na2[B12H12]. Based on the obtained data, the sample under study is an amorphous composite, on the surface of which nanoscale crystals of Na2[B12H12] form.

scholarly journals Enhancing carbonation and chloride resistance of autoclaved concrete by incorporating nano-CaCO3

2020 ◽  
Vol 9 (1) ◽  
pp. 998-1008
Author(s):  
Guo Li ◽  
Zheng Zhuang ◽  
Yajun Lv ◽  
Kejin Wang ◽  
David Hui
Keyword(s):  
Cement Hydration ◽  
Mercury Intrusion Porosimetry ◽  
Hardened Concrete ◽  
Optimal Dosage ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Carbonation Depth ◽  
X Ray ◽  
Chloride Resistance

AbstractThree nano-CaCO3 (NC) replacement levels of 1, 2, and 3% (by weight of cement) were utilized in autoclaved concrete. The accelerated carbonation depth and Coulomb electric fluxes of the hardened concrete were tested periodically at the ages of 28, 90, 180, and 300 days. In addition, X-ray diffraction, thermogravimetry, and mercury intrusion porosimetry were also performed to study changes in the hydration products of cement and microscopic pore structure of concrete under autoclave curing. Results indicated that a suitable level of NC replacement exerts filling and accelerating effects, promotes the generation of cement hydration products, reduces porosity, and refines the micropores of autoclaved concrete. These effects substantially enhanced the carbonation and chloride resistance of the autoclaved concrete and endowed the material with resistances approaching or exceeding that of standard cured concrete. Among the three NC replacement ratios, the 3% NC replacement was the optimal dosage for improving the long-term carbonation and chloride resistance of concrete.

Phase composition depth profiles using spatially resolved energy dispersive X-ray diffraction

2004 ◽  
Vol 37 (6) ◽  
pp. 967-976 ◽  
Author(s):  
Andrew C. Jupe ◽  
Stuart R. Stock ◽  
Peter L. Lee ◽  
Nikhila N. Naik ◽  
Kimberly E. Kurtis ◽  
...  
Keyword(s):  
Phase Composition ◽  
Spatial Resolution ◽  
Zinc Coating ◽  
High Energy ◽  
Sulfate Attack ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spatially Resolved ◽  
Composition Profiles

Spatially resolved energy dispersive X-ray diffraction, using high-energy synchrotron radiation (∼35–80 keV), was used nondestructively to obtain phase composition profiles along the radii of cylindrical cement paste samples to characterize the progress of the chemical changes associated with sulfate attack on the cement. Phase distributions were acquired to depths of ∼4 mm below the specimen surface with sufficient spatial resolution to discern features less than 200 µm thick. The experimental and data analysis methods employed to obtain quantitative composition profiles are described. The spatial resolution that could be achieved is illustrated using data obtained from copper cylinders with a thin zinc coating. The measurements demonstrate that this approach is useful for nondestructively visualizing the sometimes complex transformations that take place during sulfate attack on cement-based materials. These transformations can be spatially related to microstructure as seen by computed microtomography.

Quantitative Study of Al/W Interaction In Si/SiO2/W-Ti/Al Thin Film System

1988 ◽  
Vol 119 ◽  
Author(s):  
Hung-Yu Liu ◽  
Peng-Heng Chang ◽  
Jim Bohlman ◽  
Hun-Lian Tsai
Keyword(s):  
Thin Film ◽  
Film System ◽  
X Ray Diffraction ◽  
Compound Formation ◽  
X Ray ◽  
Thin Film System ◽  
Glancing Angle ◽  
Integrated Intensity ◽  
Al Thin Film ◽  
Kinetics Of

AbstractThe interaction of Al and W in the Si/SiO2/W-Ti/Al thin film system is studied quantitatively by glancing angle x-ray diffraction. The formation of Al-W compounds due to annealing is monitored by the variation of the integrated intensity from a few x-ray diffraction peaks of the corresponding compounds. The annealing was conducted at 400°C, 450°C and 500°C from 1 hour to 300 hours. The kinetics of compound formation is determined using x-ray diffraction data and verified by TEM observations. We will also show the correlation of the compound formation to the change of the electrical properties of these films.

Synthesis of CaWO4:(Eu3+,Tb3+) Thin Films by a Two-Step Method at Room Temperature

2013 ◽  
Vol 710 ◽  
pp. 170-173
Author(s):  
Lian Ping Chen ◽  
Yuan Hong Gao
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Composition ◽  
Room Temperature ◽  
Electrochemical Techniques ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Rare Earth Doped

It is hardly possible to obtain rare earth doped CaWO4thin films directly through electrochemical techniques. A two-step method has been proposed to synthesize CaWO4:(Eu3+,Tb3+) thin films at room temperature. X-ray diffraction, energy dispersive X-ray analysis, spectrophotometer were used to characterize their phase, composition and luminescent properties. Results reveal that (Eu3+,Tb3+)-doped CaWO4films have a tetragonal phase. When the ratio of n (Eu)/n (Tb) in the solution is up to 3:1, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Tb element; on the contrary, when the ratio in the solution is lower than 1:4, CaWO4:(Eu3+,Tb3+) thin film will be enriched with Eu element. Under the excitation of 242 nm, sharp emission peaks at 612, 543, 489 and 589 nm have been observed for CaWO4:(Eu3+,Tb3+) thin films.

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