scholarly journals Enhancement of barrier and anti-corrosive performance of zinc-rich epoxy coatings using nano-silica/graphene oxide hybrid

2020 ◽  
Vol 38 (6) ◽  
pp. 497-513
Author(s):  
Meiling Zhang ◽  
Hui Wang ◽  
Ting Nie ◽  
Jintao Bai ◽  
Fei Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Epoxy Coating ◽  
X Ray Diffraction ◽  
Protection Efficiency ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

AbstractThis study reports a facile method to prepare silica-coated graphene oxide nanoflakes (SiO2–GO). Results of X-ray diffraction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy reveal that silica was successfully coated on the GO flakes. The effect of SiO2–GO nanosheets on the corrosion protection and barrier performance of the epoxy coating was investigated in this work. Results indicate that the mechanical properties of all coatings added with GO and SiO2–GO were significantly improved. Furthermore, electrochemical impedance and Tafer polarisation curves showed that added 0.5 wt% SiO2–GO nanoflakes into zinc-rich epoxy coating could greatly improve the anti-corrosion performance of the sample, and the corrosion protection efficiency increased from 67.01 to 99.58%.

Preparation of a P(FcA-co-ANI)/graphene composite for application in supercapacitors

2016 ◽  
Vol 29 (5) ◽  
pp. 524-532 ◽  
Author(s):  
Yunlong Li ◽  
Yuying Zheng
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
Proton Nuclear Magnetic Resonance ◽  
Diffusion Resistance ◽  
X Ray Diffraction ◽  
Graphene Layers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Surface Morphologies

A conducting copolymer of 1,1′-ferrocenediacyl anilide and aniline (P(FcA-co-ANI)) was synthesized, which had a conjugated structure and ferrocene moieties in the main chain. The monomer and copolymer were characterized using proton nuclear magnetic resonance and Fourier-transform infrared (FTIR) spectroscopies. A P(FcA-co-ANI)/reduced graphene oxide (rGO) composite was synthesized by oxidation polymerization, using rGO as a substrate. The characteristic peaks of P(FcA-co-ANI) and rGO were observed in the FTIR spectrum of P(FcA-co-ANI)/rGO. The X-ray diffraction pattern of P(FcA-co-ANI)/rGO exhibited similar peaks to the pattern of P(FcA-co-ANI), except for the absence of the weak broad peak at 9.0° owing to rGO. The surface morphologies of the materials were characterized by atomic force microscopy, transmission electron microscopy and scanning electron microscopy. The interlayer distances of rGO and P(FcA-co-ANI)/rGO were 0.96 and 1.38 nm, respectively. The morphology of the copolymer was spherical, and it contained island structures covering the surface of the graphene layers. The electrochemical properties of the composite were measured by cyclic voltammetry, galvanostatic charge–discharge measurements and electrochemical impedance spectroscopy. The maximum specific capacitance of the composite was 722.5 F/g at 0.5 A/g. The diffusion resistance was very small, and the composites durability was sufficient for subjecting to prolonged oxidation and reduction.

(G03 Best Paper Award Winner) Analysis of Sn Behavior During Ni/GeSn Solid-State Reaction by Correlated X-ray Diffraction, Atomic Force Microscopy, and Ex-situ/In-situ Transmission Electron Microscopy

2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ex Situ ◽  
Paper Award ◽  
X Ray Diffraction ◽  
Award Winner ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Strain Relaxation During Heteroepitaxy on Twist-Bonded Thin Gallium Arsenide Substrates

1998 ◽  
Vol 535 ◽  
Author(s):  
P. Kopperschmidt ◽  
S T. Senz ◽  
R. Scholz ◽  
G. Kästner ◽  
U. Gösele ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Strain Relaxation ◽  
Twist Angle ◽  
Gaas Layer ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Compliant Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Epitaxial Deposition

AbstractWe realized “compliant” substrates in the square centimeter range by twist-wafer bonding of an (100) GaAs handle wafer to another (100) GaAs wafer with a several nm thick epitaxially grown GaAs layer followed by an appropriate back-etch procedure. The twist angle between the two GaAs wafers was chosen between 4 and 15 degrees. The twisted layers were characterized by area scanned X-ray diffraction, optical and electron microscopy and atomic force microscopy. Occasionally we observed regions showing pinholes in the transferred thin twistbonded GaAs layer.After epitaxial deposition of 300 nm InP and InGaAs films with different degrees of mismatch on these substrates, transmission electron microscopy revealed grains which are epitaxially oriented to either the substrate or the twist-bonded layer. The grain boundaries between the twisted and untwisted grains probably collect threading dislocations, thus reducing their density in the areas free of boundaries.

PLD Grown 3C-SiC Thin Films on Si: Morphology and Structure

2015 ◽  
Vol 821-823 ◽  
pp. 213-216
Author(s):  
S.M. Ryndya ◽  
N.I. Kargin ◽  
A.S. Gusev ◽  
E.P. Pavlova
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Rutherford Backscattering Spectrometry ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Selected Area Electron Diffraction ◽  
Atomic Force ◽  
Transmission Electron ◽  
Influence Of Substrate ◽  
Composition Structure

Silicon carbide thin films were obtained on Si (100) and (111) substrates by means of vacuum laser ablation of α-SiC ceramic target. The influence of substrate temperature on composition, structure and surface morphology of experimental samples was examined using Rutherford backscattering spectrometry (RBS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM), atomic force microscopy (AFM), selected area electron diffraction (SAED) and X-ray diffraction (XRD) methods.

scholarly journals Ultrashort Pulsed Laser Ablation of Magnesium Diboride: Plasma Characterization and Thin Films Deposition

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Angela De Bonis ◽  
Agostino Galasso ◽  
Antonio Santagata ◽  
Roberto Teghil
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Optical Emission ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Laser Target ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

A MgB2target has been ablated by Nd:glass laser with a pulse duration of 250 fs. The plasma produced by the laser-target interaction, showing two temporal separated emissions, has been characterized by time and space resolved optical emission spectroscopy and ICCD fast imaging. The films, deposited on silicon substrates and formed by the coalescence of particles with nanometric size, have been analyzed by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and X-ray diffraction. The first steps of the films growth have been studied by Transmission Electron Microscopy. The films deposition has been studied by varying the substrate temperature from 25 to 500°C and the best results have been obtained at room temperature.

Investigation of ZnFe2O4 Nanoparticles Prepared by High Energy Milling

2009 ◽  
Author(s):  
S. S. Srinivasan ◽  
N. Kislov ◽  
Yu. Emirov ◽  
D. Y. Goswami ◽  
E. K. Stefanakos
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Energy Gap ◽  
Blue Shift ◽  
High Energy ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Coefficient Estimation ◽  
Transmission Electron

Nanoparticles of Zinc Ferrite (ZnFe2O4) prepared by both wet- and dry- high-energy ball milling (HEBM), have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), surface area and pore size distribution (BET) and wavelength-dependent diffuse reflectance and scattering turned into absorption coefficient estimation using the Kubelka-Munk theory. It was found that after 72 hours of HEBM, the particle size was decreased from 220 nm for the initial material to 16.5 nm and 9.4 nm for the wet- and dry-milled samples, respectively. The optical absorption analysis revealed that the energy gap is increased (blue shift) by 0.45 eV for wet-milled and decreased (“anomalous” red shift) by 0.15 eV for dry-milled samples of ZnFe2O4 as the particle size decreased.

scholarly journals SYNTHESIS OF NANO-ALUMINUM OXIDE VIA BIOLOGICAL AND ELECTROCHEMICAL METHODS

2019 ◽  
Vol 29 (4) ◽  
pp. 67
Author(s):  
Barakat A. F. Kamel
Keyword(s):  
Electron Microscopy ◽  
Aluminum Oxide ◽  
Pathogenic Bacteria ◽  
Research Work ◽  
Alumina Nanoparticles ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Stable Particles

In this research work, the nanoparticles of aluminum oxide were synthesized by two ways. The first way is the biological by using (Pseudomonas aeruginosa) bacteria with a rate diameter (102.35) nm. The second way is the electrochemical with a rate diameter (62) nm. These nanoparticles were characterized by Atomic Force Microscopy (AFM), X-Ray diffraction technique (XRD), Transmission Electron Microscopy (TEM) and Scanninig Electron Microscopy (SEM). Alumina nanoparticles are thermodynamically stable particles over a wide temperature range . The biological activity of these nanoparticles toward different species of pathogenic bacteria (Staphylococcus aureus ) and (Pseudo monas) has been investigated. The results stated that the nanoparticles prepared by chemical way was more effective on the inhibition of bacteria than the nanoparticles prepared by biological way

scholarly journals Development of one-dimensional titania nanomaterials

2014 ◽  
Author(s):  
Ναούμ Βαενάς
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Impedance ◽  
Linear Sweep Voltammetry ◽  
Linear Sweep ◽  
One Dimensional ◽  
Force Microscopy ◽  
Photocurrent Spectroscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dye Solar Cells

Σκοπός αυτής της διδακτορικής διατριβής είναι η ανάπτυξη μονοδιάστατων νανοδομών τιτανίας και εν συνεχεία η εφαρμογή τους στην κατασκευή ευαισθητοποιημένων ηλιακών κελιών (Dye Solar Cells - DSCs). Οι νανοσωλήνες τιτανίας αποτελούν την ιδανική επιλογή για τους στόχους αυτής της έρευνας καθώς: α) μπορούν να προετοιμαστούν εύκολα από την ανοδική οξείδωση ενός φύλλου τιτανίου, β) επιτρέπουν τον εύκολο έλεγχο της μορφολογίας τους μέσω της ηλεκτροχημικής νάνο-μηχανικής, γ) εξασφαλίζουν εξαιρετικές ηλεκτρικές ιδιότητες, όπως κατευθυνόμενη κίνηση των ηλεκτρονίων. Οι νανοσωλήνες τιτανίας χρησιμοποιήθηκαν ως ηλεκτρόδια εργασίας (photo-anodes) στα ευαισθητοποιημένα ηλιακά κελιά που κατασκευάστηκαν στη συνέχεια.Τα μορφολογικά και δομικά χαρακτηριστικά των νανοσωλήνων μελετήθηκαν με τις τεχνικές, της μικροσκοπίας ατομικών δυνάμεων (Atomic Force Microscopy - AFM), της μικροσκοπίας ηλεκτρονικής σάρωσης (Scanning Electron Microscopy - SEM), της μικροσκοπίας ηλεκτρονικής διελεύσεως (Transmission Electron Microscopy - TEM), της φασματοσκοπίας υπεριώδους/ορατού (Ultraviolet–Visible - UV-Vis) και της φασματοσκοπίας Ράμαν (Raman spectroscopy). Επιπλέον η αξιολόγηση και ο χαρακτηρισμός των ηλιακών κελιών πραγματοποιήθηκε με τις μεθόδους, της φασματοσκοπίας ηλεκτροχημικής εμπέδησης (Electrochemical Impedance Spectroscopy - EIS), της φασματοσκοπίας φωτοδυναμικού/φωτορεύματος περιοδικά μεταβαλλόμενης έντασης φωτισμού (Intensity Modulated Photovoltage/ Photocurrent Spectroscopy - IMVS/IMPS) και τελικά οι αποδόσεις των φωτοβολταϊκών εξάχθηκαν από την βολταμετρία φωτορεύματος (Linear Sweep Voltammetry - LSV). Κίνητρα για αυτήν την μελέτη αποτέλεσαν η ανάγκη κατανόησης, των βασικών μηχανισμών ανάπτυξης των νανοσωλήνων τιτανίας καθώς και των αρχών λειτουργίας που διέπουν τα ευαισθητοποιημένα ηλιακά κελιά. Στο πρώτο μέρος αυτής της έρευνας πραγματοποιήθηκαν μερικά προκαταρτικά πειράματα, με σκοπό την βελτίωση της μορφολογίας του χρησιμοποιούμενου υποστρώματος τιτανίου, όπως και των νανοσωλήνων τιτανίας που προέκυψαν. Μόλις οι συνθήκες ανοδίωσης σταθεροποιήθηκαν, υψηλής ομοιογένειας και ποιότητας νανοσωλήνες προετοιμάστηκαν και χρησιμοποιήθηκαν σε ευαισθητοποιημένα ηλιακά κελιά με ικανοποιητική απόδοση. Στην δεύτερη φάση αυτού του έργου, οι δομικές ιδιότητες των νανοσωλήνων μελετήθηκαν , με σκοπό να εξασφαλιστεί η ανεμπόδιστη μεταφορά των ηλεκτρονίων. Συγκεκριμένα η επίδραση της διαδικασίας απόπτυσης των νανοσωλήνων διερευνήθηκε συνάρτηση των ηλεκτρικών χαρακτηριστικών των φωτοβολταϊκών συσκευών που τελικά παράχθηκαν. Στο τρίτο στάδιο της διατριβής, προηγμένες δομές νανοσωλήνων προετοιμάσθηκαν μέσω σύνθετων τρόπων ανοδίωσης. Η ποτενσιοστατική και γαλβανοστατική ανοδίωση συνδυάστηκαν για πρώτη φορά στην βιβλιογραφία και οδήγησαν στην εξέλιξη της μεθόδου της ανοδίωσης. Το τελευταίο μέρος της δουλειάς αφιερώθηκε αποκλείστηκα στην αύξηση της απόδοσης των φωτοβολταϊκών που ενσωμάτωναν φωτοηλεκτροδία νανοσωλήνων, μέσω της χρήσης των πιο σύγχρονων ηλεκτρολυτών και χρωστικών. Το οξειδοαναγωγικό ζεύγος κοβαλτίου διαχύθηκε με ευκολία στους πορώδους νανοσωλήνες και σε συνδυασμό με την οργανική χρωστική D35, οδήγησε σε υψηλές φωτοτάσεις και αποδόσεις.

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