Hot Corrosion Monitoring of Waste Incineration Corrosion Processes Using Electrochemical Techniques

2006 ◽  
Vol 522-523 ◽  
pp. 531-538 ◽  
Author(s):  
F.J. Pérez ◽  
J. Nieto ◽  
J.A. Trilleros ◽  
M.P. Hierro
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Waste Incineration ◽  
Corrosion Monitoring ◽  
Spinel Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cr2o3 Scale ◽  
Electrochemical Processes ◽  
Salt Mixtures

In order to evaluate the damage of molten salt mixtures in waste incineration environments, the alloy 625 was exposed to a molten KCl-ZnCl2 mixture at 650 °C for 200 hours. The corrosion process was monitored by electrochemical impedance spectroscopy (EIS). After exposure the corrosion products were analyzed by X-ray diffraction and SEM. Two different electrochemical impedance models were found to describe the electrochemical processes. In the early stages of corrosion the alloy developed a protective Cr2O3 scale which turned into a porous spinel oxide scale after 100 hours.

Evaluation of Polymeric Coatings in CO2 Containing Environment

2019 ◽  
Vol 965 ◽  
pp. 133-141
Author(s):  
Rayane Z.C. Demoner ◽  
Alexandre R.P. Castro ◽  
Adriana L. Barros ◽  
J.P. Quintela ◽  
Jefferson R. de Oliveira ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Polymeric Coating ◽  
Metallic Surface ◽  
Polymeric Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Linear Polarization Resistance ◽  
Weight Loss Method ◽  
Loss Method

Two types of polymeric coating were applied on an AISI 1020 steel, where one of them was reinforced by carbon nanotubes, with the objective of protection against corrosion in a medium containing saline solution, NaCl 3% wt satured with CO2, at 75 bar and tested at 50oC and 75oC for 360 hours. Electrochemical techniques, such as Linear Polarization Resistance, (LPR), Electrochemical Impedance Spectroscopy (EIS), Tafel curves and weight loss method, were used for coating evaluation performance. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) were used to determine both the morphology and chemical composition of the layer formed on the analyzed surfaces. The coating adhesion to metallic surface was evaluated using pull-off test according to ASTM D4541-09. For the studied conditions, the results obtained showed that there was no adequate coating protection, occurring failures and indicating that both coatings may not be used in the tested conditions.

Effect of Zn Content on Structure, Roughness and Corrosion Behavior of Zn-Ni Alloys

2019 ◽  
Vol 17 (17) ◽  
pp. 17-22
Author(s):  
Hayette Faid
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Stripping Voltammetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ni Alloys ◽  
Sulfate Bath ◽  
Zn Content ◽  
Polarization Test ◽  
Δ Phase

AbstractIn this work, Zn-Ni alloys have been deposited on steel from sulfate bath, by electrodeposition method. The effect of Zn content on deposits properties was studied by cyclic voltammetry (CV), chronoaperometry (CA), linear stripping voltammetry (ALSV) and diffraction (XRD) and scanning electronic microscopy (SEM). The corrosion behavior in 3.5 wt. NaCl solution was examined using anodic polarization test and electrochemical impedance spectroscopy. X-ray diffraction of show that Zn-Ni alloys structure is composed of δ phase and γ phase, which increase with the decrease of Zn content in deposits. Results show that deposits obtained from bath less Zn2+ concentration exhibited better corrosion resistance.

Characterizations of Synthetic 8mol% YSZ with Comparison to 3mol %YSZ for HT-SOFC

2020 ◽  
Vol 38 (4A) ◽  
pp. 491-500
Author(s):  
Abeer F. Al-Attar ◽  
Saad B. H. Farid ◽  
Fadhil A. Hashim
Keyword(s):  
Ionic Conductivity ◽  
Electrochemical Impedance ◽  
Structural Information ◽  
Impedance Analysis ◽  
High Energy ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Powder Morphology ◽  
X Ray

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

scholarly journals Effect of Molybdenum Content on the Corrosion and Microstructure of Low-Ni, Co-Free Maraging Steels

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 852
Author(s):  
Asiful H. Seikh ◽  
Hossam Halfa ◽  
Mahmoud S. Soliman
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Microstructural Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
X Ray ◽  
Maraging Steels ◽  
Eds Analysis ◽  
Electroslag Refining

Molybdenum (Mo) is an important alloying element in maraging steels. In this study, we altered the Mo concentration during the production of four cobalt-free maraging steels using an electroslag refining process. The microstructure of the four forged maraging steels was evaluated to examine phase contents by optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. Additionally, we assessed the corrosion resistance of the newly developed alloys in 3.5% NaCl solution and 1 M H2SO4 solution through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Furthermore, we performed SEM and energy-dispersive spectroscopy (EDS) analysis after corrosion to assess changes in microstructure and Raman spectroscopy to identify the presence of phases on the electrode surface. The microstructural analysis shows that the formation of retained austenite increases with increasing Mo concentrations. It is found from corrosion study that increasing Mo concentration up to 4.6% increased the corrosion resistance of the steel. However, further increase in Mo concentration reduces the corrosion resistance.

Few-Layered MoS2 Nanostructures for Highly Efficient Visible Light Photocatalysis

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650114 ◽  
Author(s):  
Dan Li ◽  
Jianwei Li ◽  
Caiqin Han ◽  
Xinsheng Zhao ◽  
Haipeng Chu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Electrochemical Impedance ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Electrochemical Impedance Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Hole Pair

Few-layered MoS2 nanostructures were successfully synthesized by a simple hydrothermal method without the addition of any catalysts or surfactants. Their morphology, structure and photocatalytic activity were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electrochemical impedance spectra and UV-Vis absorption spectroscopy, respectively. These results show that the MoS2 nanostructures synthesized at 180[Formula: see text]C exhibit an optimal visible light photocatalytic activity (99%) in the degradation of Rhodamine B owing to the relatively easier adsorption of pollutants, higher visible light absorption and lower electron–hole pair recombination.

Structure and Electrochemical Behavior of Plasma-Sprayed LSGM Electrolyte Films

2002 ◽  
Vol 756 ◽  
Author(s):  
H. Zhang ◽  
X. Ma ◽  
J. Dai ◽  
S. Hui ◽  
J. Roth ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Amorphous Structure ◽  
Solid Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Electrolyte Film ◽  
Plasma Sprayed

ABSTRACTAn intermediate temperature solid oxide fuel cell (SOFC) electrolyte film of La0.8Sr 0.2Ga0.8Mg0.2O2.8 (LSGM) was fabricated using a plasma spray process. The microstructure and phase were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical behavior of the thermal sprayed LSGM film was investigated using electrochemical impedance spectroscopy (EIS). The study indicates that thermal spray can deposit a dense LSGM layer. It was found that the rapid cooling in the thermal process led to an amorphous or poor crystalline LSGM deposited layer. This amorphous structure has a significant effect on the performance of the cell. Crystallization of the deposited LSGM layer was observed during annealing between 500–600 °C. After annealing at 800 °C, the ionic conductivity of the sprayed LSGM layer can reach the same level as that of the sintered LSGM.

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.

scholarly journals Χαρακτηρισμός πολυμερικών επιστρώσεων με νανοπερίεκτες σε μέταλλα για την προστασία τους από διάβρωση σε θαλάσσιο περιβάλλον

2012 ◽  
Author(s):  
Ανδρόνικος Μπαλάσκας
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organically Modified Silicates ◽  
Organically Modified ◽  
Ft Ir ◽  
Scanningelectron Microscopy

Υβριδικές επιστρώσεις οργανικά τροποποιημένων πυριτικών ενώσεων και εποξειδικώνρητινών (Organically Modified Silicates, ORMOSILs – epoxy) εφαρμόστηκαν στο κράμααργιλίου 2024-Τ3 και σε γαλβανισμένο χάλυβα σε υψηλές θερμοκρασίες (Hot Dip GalvanizedSteel, HDGS) προκειμένου αυτές να προστατεύσουν τα υποστρώματα από τη διάβρωση. Για τηνβελτίωση της αντοχής των επιστρώσεων στην διάβρωση ενσωματώθηκαν στην πολυμερικήμήτρα νανοπεριέκτες από μολυβδαινικό δημήτριο (CeMo) και οξείδιο του τιτανίου (TiO2),καθώς και pH-ευαίσθητα οργανικά νανοδοχεία πληρωμένα με τους αναστολείς διάβρωσης 2-μερκαπτοβενζοθειαζόλιο, 8-υδροξυκινολίνη, 1H-βενζοτριαζολο-4-σουλφονικό οξύ καιεξαφλουοροτιτανικό οξύ.Οι υβριδικές επιστρώσεις εφαρμόστηκαν στο υπόστρωμα με τη διαδικασία εμβάπτισης.Η μορφολογία των επιστρώσεων εξετάστηκε με ηλεκτρονική μικροσκοπία σάρωσης (ScanningElectron Microscopy (SEM)). Η σύνθεση και η δομή τους μελετήθηκε με υπέρυθρηΦασματοσκοπία μετασχηματισμού Fourier (FT-IR) και με μικροανάλυση με φθορισμομετρίαακτίνων Χ (Energy Dispersive X-Ray Analysis (EDX)). H ηλεκτροχημική φασματοσκοπίασύνθετης αντίστασης (Electrochemical Impedance Spectroscopy, EIS), η dc-πόλωση (dcpolarization)και η μέτριση ανοικτού δυναμικού (open circuit potential, OCP) χρησιμοποιήθηκανγια την αξιολόγηση των αντι-διαβρωτικών ιδιοτήτων των επιστρώσεων. Τα αποτελέσματαέδειξαν ότι οι επιστρώσεις με πληρωμένα νανοδοχεία έχουν αυξημένες αντιδιαβρωτικέςιδιότητες συγκριτικά με τις υπόλοιπες επιστρώσεις εμφανίζοντας και ιδιότητες αυτο-θεραπείας.Τέλος, συντέθηκαν νανόσφαιρες οξειδίου του χαλκού (Cu2O), οι οποίεςχαρακτηρίστηκαν με SEM, ηλεκτρονική μικροσκοπία διερχόμενης δέσμης (ΤransmissionΕlectron Μicroscopy (TEM)) και περίθλαση ακτίνων Χ (X ray Diffraction (XRD)). Οινανόσφαιρες στη συνέχεια πληρώθηκαν με ουσίες που δρουν ως βιοκτόνα και ενσωματώθηκανσε βαφές εμπορίου και σε επιστρώσεις βασισμένες σε εποξειδικές ενώσεις και μελετήθηκε ηδράση τους ως αντιαποθετικά αντιδραστήρια. Τα αποτελέσματα έδειξαν ότι οι επιστρώσεις μεπληρωμένες νανόσφαιρες Cu2O είχαν μεγαλύτερη αποτελεσματικότητα σε σύγκριση με τιςβαφές εμπορίου με βιοκτόνα μετά από έκθεση σε θαλάσσιο περιβάλλον.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND CORROSION RESISTANCE OF Ni-B-W-Mo COATING DEPOSITED BY ELECTROLESS METHOD

2018 ◽  
Vol 25 (08) ◽  
pp. 1950023 ◽  
Author(s):  
ARKADEB MUKHOPADHYAY ◽  
TAPAN KUMAR BARMAN ◽  
PRASANTA SAHOO
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electrochemical Techniques ◽  
Sodium Molybdate ◽  
Medium Carbon Steel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Heat Treated ◽  
Electroless Coatings

The present work reports the deposition of a quaternary Ni-B-W-Mo coating on AISI 1040 medium carbon steel and its characterization. Quaternary deposits are obtained by suitably modifying existing electroless Ni-B bath. Composition of the as-deposited coating is analyzed by energy dispersive X-ray spectroscopy. The structural aspects of the as-deposited and coatings heat treated at 300[Formula: see text]C, 350[Formula: see text]C, 400[Formula: see text]C, 450[Formula: see text]C and 500[Formula: see text]C are determined using X-ray diffraction technique. Surface of the as-deposited and heat-treated coatings is examined using a scanning electron microscope. Very high W deposition could be observed when sodium molybdate is present in the borohydride-based bath along with sodium tungstate. The coatings in their as-deposited condition are amorphous while crystallization takes place on heat treatment. A nodulated surface morphology of the deposits is also observed. Vickers’ microhardness and crystallite size measurement reveal inclusion of W and Mo results in enhanced thermal stability of the coatings. Solid solution strengthening of the electroless coatings by W and Mo is also observed. The applicability of kinetic strength theory to the hardening of the coatings on heat treatment is also investigated. Corrosion resistance of Ni-B-W-Mo coatings and effect of heat treatment on the same are also determined by electrochemical techniques.

Effect of Zirconium Oxide Reinforcement on Microstructural, Electrochemical and Mechanical Properties of TiNi Alloy Produced Via Powder Metallurgy Route

2021 ◽  
pp. 1-22
Author(s):  
Syed Abbas Raza ◽  
Muhammad Imran Khan ◽  
Muhammad Ramzan Abdul karim ◽  
Rashid Ali ◽  
Muhammad Umair Naseer ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Passive Layer ◽  
Charge Transfer Resistance ◽  
Tini Alloy ◽  
X Ray Diffraction ◽  
Zro2 Content ◽  
Transfer Resistance ◽  
X Ray ◽  
Conventional Sintering ◽  
Layer Resistance

Abstract Equiatomic TiNi alloy composites, reinforced with 0, 5, 10 and 15 vol. % ZrO2, were synthesized using conventional sintering approach. Equiatomic TiNi pre-alloyed powder and ZrO2 powder were mixed in planetary ball mill for 6 hours followed by cold compaction and pressure-less sintering, respectively. The sintered density was found to vary inversely with the addition of ZrO2 content. The X-Ray diffraction spectra have shown the formation of multiple-phases which were resulted from the decomposition of the B19'and B2 phases of the equiatomic TiNi alloy due to the addition of ZrO2 and higher diffusion rate of Ni than that of Ti in the alloy composite. An increase in hardness was noted due to the addition of ZrO2, measured by micro and nanoindentation techniques. Potentiodynamic polarization scan revealed a 10% decrease in the corrosion rate of the composite containing 10 vol. % ZrO2. Electrochemical impedance spectroscopy results indicated an increase in passive layer resistance (Rcoat) due to the increase in charge transfer resistance (Rct) caused by the reduced leaching of ions from the surface.

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