Growth and Characterization of a Combinatorial Array of Mixed-Phase Magnesium-Aluminum Thin-Film Alloys

2007 ◽  
Vol 1056 ◽  
Author(s):  
Charles Olk ◽  
Daad B. Haddad

ABSTRACTCombinatorial gradient-controlled sputter deposition has been employed to produce a library of 100 separate thin films with a wide range of Mg-Al alloy compositions. We have successfully isolated the â (Mg17Al12) phase in polycrystalline films for investigation. The presence of the â phase has been found to be desirable for increasing corrosion resistance; however, in structural components under tensile loading and/or at elevated temperatures, the â phase precipitates undergo coarsening which induces poor creep behavior in several common alloys. We have also synthesized amorphous Mg-Al and mixed-phase compositions as identified by X-ray diffraction measurements. Details of the growth procedure as well as structural and compositional characterization are presented.

1995 ◽  
Vol 395 ◽  
Author(s):  
S. A. Ustin ◽  
L. Lauhon ◽  
K. A. Brown ◽  
D. Q. Hu ◽  
W. Ho

ABSTRACTHighly oriented aluminum nitride (0001) films have been grown on Si(001) and Si (111) substrates at temperatures between 550° C and 775° C with dual supersonic molecular beam sources. Triethylaluminum (TEA;[(C2H5)3Al]) and ammonia (NH3) were used as precursors. Hydrogen, helium, and nitrogen were used as seeding gases for the precursors, providing a wide range of possible kinetic energies for the supersonic beams due to the disparate masses of the seed gases. Growth rates of AIN were found to depend strongly on the substrate orientation and the kinetic energy of the incident precursor; a significant increase in growth rate is seen when seeding in hydrogen or helium as opposed to nitrogen. Growth rates were 2–3 times greater on Si(001) than on Si(111). Structural characterization of the films was done by reflection high energy electron diffraction (RHEED) and x-ray diffraction (XRD). X-ray rocking curve (XRC) full-width half-maxima (FWHM) were seen as small as 2.5°. Rutherford back scattering (RBS) was used to determine the thickness of the films and their chemical composition. Films were shown to be nitrogen rich, deviating from perfect stoichiometry by 10%–20%. Surface analysis was performed by Auger electron spectroscopy (AES).


Author(s):  
Tarun Goyal ◽  
T. S. Sidhu ◽  
R. S. Walia

This study reveals the successful low pressure cold spray deposition of near-uniform, defect free and dense copper coatings approximately 700-1900 µm thick, on Al alloy for electro-technical applications. The micro structural characteristics of the deposits have been studied using the combined techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) and electron-probe micro analysis (EPMA). The coatings exhibited characteristic splat-like, layered morphologies due to the deposition of solid powder particles which appeared to have been plastically deformed on impact to the substrate. The developed coatings have a dense (in the range of 3090-5015 kg/m3)and nearly uniform microstructure, with almost uniform hardness values in the range of 120 -140 Hv, and electrical conductivity in the range of 23-30 MS/m. EDAX, XRD and EPMA results revealed that the main constituent in the coating is Cu.


Chemistry ◽  
2020 ◽  
Vol 2 (2) ◽  
pp. 591-599
Author(s):  
Brock A. Stenfors ◽  
Richard J. Staples ◽  
Shannon M. Biros ◽  
Felix N. Ngassa

Treatment of 2,4-dinitrophenol with sulfonyl chlorides in the presence of pyridine results in the formation of undesired pyridinium salts. In non-aqueous environments, the formation of the insoluble pyridinium salt greatly affects the formation of the desired product. A facile method of producing the desired sulfonate involves the use of an aqueous base with a water-miscible solvent. Herein, we present the optimization of methods for the formation of sulfonates and its application in the production of desired x-substituted 2,4-dinitrophenyl-4′-phenylbenzenesulfonates. This strategy is environmentally benign and supports a wide range of starting materials. Additionally, the intermolecular interactions of these sulfonate compounds were investigated using single-crystal x-ray diffraction data.


2006 ◽  
Vol 45 ◽  
pp. 2483-2488
Author(s):  
L. Pablos ◽  
Maria Elena Villafuerte-Castrejón ◽  
A. Ibarra-Palos ◽  
J. Ocotlán-Flores ◽  
R. Sato ◽  
...  

PbBi4Ti4O15 belongs to the bismuth oxide layers family discovered by Aurivillius more than 50 years ago. In the last few years, there has been considerable interest in layered oxides exhibiting ferroelectric, piezoelectric and other related properties due to their wide range of application in technical devices. In the present work the PbBi4Ti4O15 solid solution formed with Eu3+ was synthesized by coprecipitation method and solubility limit was found. All compounds were characterized by scanning electron microscopy, density measurements and X-ray diffraction. The variation of lattice parameter with the Eu3+ concentration was obtained. Raman spectroscopy was carried out in order to determine the Eu3+ site in the lattice. Thermal analysis (thermogravimetry and differencial scanning calorimetry) results are also presented.


2018 ◽  
Vol 64 (3) ◽  
pp. 206
Author(s):  
R. S. Castillo Ojeda ◽  
Joel Díaz-Reyes ◽  
M. Galván-Arellano ◽  
K. N. Rivera-Hernández ◽  
M. S. Villa-Ramírez ◽  
...  

In this work are presented the results obtained from the deposition ofCd1-xZnxTe nanolayers using as precursor the vapours of the elementsZn, Te, and a mixture of Cd and Zn on GaAs and GaSb (001) substrates by Atomic Layer Deposition technique (ALD), which allows the deposition of layers of nanometric dimensions. At each exposure of the growth surface to the of cation or anion precursors vapours, this surface is saturated. Therefore, it is considered that the process is self-regulated. The ZnTe layers were grown in a wide range of temperatures; however, ZnTe nanolayers with a shiny mirror-like surface could be grown at temperatures between 370 and 410oC. Temperatures higher than 400oC were necessary for the CdTe growth. The layers of the Cd1-xZnxTe ternary alloy were deposited at temperature range of 400 and 425oC. The grown nanofilms were characterized by Raman spectroscopy and high-resolution X-ray diffraction. The Raman spectrumshows the peak corresponding to LO-ZnTe at 208 cm-1, which is weak and is slightly redshifted in comparison with the reported for the bulk ZnTe. For the case of the CdTe nanolayers, Raman spectrum presents the LO-CdTe peak, which is indicative of the successfully growth of the nanolayers, its weakness and its slight redshifted in comparison with the reported for the bulk CdTe can be related with the nanometric characteristic of this layer. The performed high resolution X-ray diffraction measurements allowed to study some importantcharacteristics, as the crystallinity of the grown layers. Additionally, the performed HR-XRD measurements suggest that the crystalline quality have dependence with the growth temperature.


Cerâmica ◽  
2003 ◽  
Vol 49 (312) ◽  
pp. 223-227 ◽  
Author(s):  
C. dos Santos ◽  
S. Ribeiro ◽  
K. Strecker ◽  
C. R. M. da Silva

Silicon nitride is a covalent ceramic material of high corrosion resistance and mechanical stability at elevated temperatures. Due to these properties, its use in metallurgical processes, such as the casting of alloys, is increasing. Therefore, the characterization of the interface between Si3N4 and the casted metal is of great importance to investigate possible interactions, which might deteriorate the ceramic mould or contaminate the metal. In this work, the use of Si3N4 as crucible material for Al-casting has been studied, by investigating the corrosion attack of liquid Al at a temperature of 1150 ºC during 30 days in air. The interface was characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. It has been found that due to superficial oxidation two oxide layers form - SiO2 on Si3N4 and Al2O3 on Al - which effectively hinder further reactions under the conditions studied, confering high corrosion resistance to the Si3N4 crucible.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nalin Somani ◽  
Navjot Singh ◽  
Nitin Kumar Gupta

Purpose The purpose of this paper is to based upon the joining and characterization (mechanical and metallurgical) of ferritic stainless steel (SS)-430 using a microwave hybrid heating (MHH) phenomenon. Design/methodology/approach The preliminary experiments were conducted using nickel-based powder as interface material using a domestic microwave oven at a frequency of 2.45 GHz and 900 W power for 720 s. The processed joint was metallurgically characterized by means of X-ray diffraction, Energy-dispersive X-ray spectroscopy and Field emission scanning electron microscopy. Mechanical characterization was done by means of tensile and Vickers’ microhardness testing to check the hardness and strength of the joint. Findings The metallurgical study revealed that the microstructure and formation of numerous phases of Fe2Si3 accompanied by chromium and nickel carbides. The average hardness of 359 Hv at the center of the joint and 637 Hv around the boundaries of the joint was observed. The tensile strength of the joint was observed to 471 MPa with an elongation of 9.02%. The worn surface of the joint signifies the presence of plastic deformation and it was limited due to the presence of harder phases such as Ni3Si and Ni3C. Research limitations/implications The concept of microwave joining of metals is a very challenging task as the temperature can not be controlled in the inert atmosphere of the microwave. It has been also observed that at certain elevated temperatures, the material starts absorbing the microwaves; which is unknown. So, a more intensive study is required to overcome these kinds of limitations. Practical implications MHH technique can be used to process different materials such as ceramics, composites and polymers. SS-430 joined by microwave heating is highly corrosion resistive and has wide applications in refrigerators cabinet panels, dishwasher linings, chimney liners, lashing wires, etc. Originality/value As of the author’s best knowledge, no work has been reported on the joining of SS-430 which has huge potential in the industries. Also, no work has been reported on the characterization of microwave joined SS-430.


2019 ◽  
Vol 9 (2) ◽  
pp. 3915-3917
Author(s):  
S. Akhtar ◽  
Z. Farid ◽  
H. Ahmed ◽  
S. A. Khan ◽  
Z. N. Khan

Silver (Ag) nanoparticles (NPs) are synthesized and characterized by a low-cost chemical reduction method. Silver nanoparticles (Ag NPs) have pre-occupied the consideration of the scientific community due to their wide range of functions, utility and industrial applications, particularly in the fields of sensing technologies and medicine (particularly their efficiency against microbes, the ability of healing the wound and anti-inflammatory properties). Ag NPs are synthesized by a low-cost fabrication method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX) and photometry techniques are used in this work to identify their nature and potentiality for diverse applications in sensing technologies.


Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 35
Author(s):  
Blanca Yamile Rosas ◽  
Alvaro A. Instan ◽  
Karuna Kara Mishra ◽  
S. Nagabhusan Achary ◽  
Ram S. Katiyar

The compound 0.9[KNbO3]-0.1[(BaNi1/2Nb1/2O3−δ] (KBNNO), a robust eco-friendly (lead-free) ferroelectric perovskite, has diverse applications in electronic and photonic devices. In this work, we report the dielectric, ferroelectric, and structural phase transitions behavior in the KBNNO compound using dielectric, X-ray diffraction, and Raman studies at ambient and as a function of temperature. Analyses of X-ray diffraction (XRD) data at room temperature (rtp) revealed the orthorhombic phase (sp. Gr. Amm2) of the compound with a minor secondary NiO cubic phase (sp. Gr. Fm3m). A direct optical band gap Eg of 1.66 eV was estimated at rtp from the UV–Vis reflectance spectrum analysis. Observation of non-saturated electric polarization loops were attributed to leakage current effects pertaining to oxygen vacancies in the compound. Magnetization studies showed ferromagnetism at room temperature (300 K) in this material. XRD studies on KBNNO at elevated temperatures revealed orthorhombic-to-tetragonal and tetragonal-to-cubic phase transitions at 523 and 713 K, respectively. Temperature-dependent dielectric response, being leaky, did not reveal any phase transition. Electrical conductivity data as a function of temperature obeyed Jonscher power law and satisfied the correlated barrier-hopping model, indicating dominance of the hopping conduction mechanism. Temperature-dependent Raman spectroscopic studies over a wide range of temperature (82–673 K) inferred the rhombohedral-to-orthorhombic and orthorhombic-to-tetragonal phase transitions at ~260, and 533 K, respectively. Several Raman bands were found to disappear, while a few Raman modes such as at 225, 270, 289, and 831 cm−1 exhibited discontinuity across the phase transitions at ~260 and 533 K.


Author(s):  
Michal P. Dybowski ◽  
Piotr Holowinski ◽  
Rafal Typek ◽  
Andrzej L. Dawidowicz

Abstract Purpose The purpose of the study was to evaluate a complete analytical and structural characterization of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA), a novel synthetic cannabinoid being the analogue of 5F-ADB. Methods The compound was analyzed by gas chromatography–mass spectrometry (GC–MS), high-resolution liquid chromatography–mass spectrometry (LC–MS), X-ray diffraction and spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies. To derive MDMB-4en-PINACA molecular geometry and to assign infrared absorption bands, quantum calculations with the employment of density functional theory were also used. Results We present a wide range of chromatographic and spectroscopic data supported with theoretical calculations allowing to identify MDMB-4en-PINACA. Conclusions To our knowledge, this is the first report presenting a comprehensive analytical and structural characterization of MDMB-4en-PINACA obtained by 1D and 2D NMR, GC–MS, LC–MS(/MS), attenuated total reflection-FTIR spectroscopy, powder X-ray diffraction and quantum chemical calculations. The presented results not only broaden the knowledge about this psychoactive substance but also are useful for forensic and clinical purposes.


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