bluuebunny/crossref_metadata_2025_split huggingface dataset:
Corrosion of High Temperature Materials in Fluoride and Chloride Molten Salts
Authors: Fuentes Roderick Eliel , Olson Luke Christopher , Martinez-Rodriguez Michael Joe , Gray Joshua R. , Garcia-Diaz Brenda Lee 
Published: February 2020

Concentrating solar power (CSP) systems that can operate at higher temperatures than 800°C can achieve higher efficiencies and power production using high temperature power cycles. Operating at these temperatures requires identifying heat transfer fluids and materials for construction of heat transfer systems that will provide good operating characteristics and long system lifetimes. Advanced power cycles such as the supercritical CO2 Brayton cycle can operate above 800°C and molten salts are one of the best options to transfer heat at these conditions due to their very high boiling points and good heat transfer properties. However, a potential drawback with using molten salts at high temperatures is materials corrosion. Therefore, it is important to identify pairs of heat transfer materials and molten salts that will have the mechanical properties and chemical stability to provide long system lifetimes. Several alloys that can be used for high temperature operation includes alloys with high nickel and chromium content, such as Haynes 230, and high cobalt and chromium content, such as Haynes NS-163. However, weight loss by dealloying of chromium from high temperature alloys containing chromium was observed when exposed to FLiNaK at 850°C for 500 hrs1. In this work, several high temperature alloys such Haynes 230 and NS-163, TZM and a SiC/SiC composite were exposed to molten KCl-MgCl2 and FLiNaK at temperature 750, 850 and 950°C for a long term period. The alloys were examined via SEM/EDS post corrosion at the surface and cross-section to account for the corrosion attack and element depletion from bulk. The salts were analyzed via ICP-OES to quantify the elements that were depleted and diffused into the salt.
Reference:
1. L.C. Olson, J. W. Ambrosek, K. Sridharan, M. H. Anderson and T. R. Allen, Journal of Fluorine Chemistry, 130(1), 67-73 (2009).
High Temperature Electrochemical Evaluation of Ni Based Coatings Deposited by Laser Ablation
Authors: Estrada Ariadna Trujillo , Miramontes Jose Angel Cabral , Aguilar Pedro Antonio Márquez , Hernández Adalberto Castro , Robledo Patricia Zambrano , Tiburcio Citlalli Gaona , Calderón Facundo Almeraya 
Published: February 2020

INTRODUCTION
Among the wide variety of coating applications Laser Ablation [1,2], we can find an alternative for the lifetime of the materials used in aggressive media, such as molten salts which cause various damages and losses are substantially represented in the industry [3,4].
METHODOLOGY
SA213-T22 the steel is used as substrate for the deposition of coatings based Ni a shot blast treatment before the coating is applied leaving the surface to which this list to be anchored correctly. The electrochemical tests were done with a 3-electrode cell (RE, AE w1) [3] at two temperatures 25 ° and 700 ° C.
RESULTS
Figure 1 shows two linear polarization can be observed at a higher temperature than the corrosion rate decreases and the potential Icorr is more active presents.
CONCLUSIONS
The laser coatings represent an alternative to tackle the process of high temperature corrosion by molten salts as these may have greater strength than other materials.
Electrochemical techniques are a useful tool for assessing coatings by laser Ablation molten salt alternative.
REFERENCES
[1] Ferrari, B., R. Moreno, T. Benito, M. T. Larrea, and J. C. Fariñas. Revista de Metalurgia 34, no. Extra (1998): 22-26.
[2] M. Badrossamay, T.H.C. Childs, Volume 47, Issue 5, April 2007, Pages 779-784, ISSN 0890-6955
[3] Almeraya, F., A. Martinez-Villafañe, C. Gaona, M. A. Romero, and J. M. Malo. Revista de metalurgia 34, no. 1 (1998): 11-17.
[4] Tristancho, José Luis, Facundo Almeraya, and José Chacón. Scientia et Technica 3, no. 46 (2010): 163-167.
Electrochemical Analysis of Temperature, Concentration and Velocity Effects in Naphthenic Acid Corrosion of 5%Cr-1%Mo Steel
Authors: Escorcia Rojas Kely Margarita , Laverde Cataño Dionicio Antonio 
Published: February 2020

Abstract:

When heavy oil are submitted to high temperature and stirring conditions as found in the furnaces that belongs to preheating-section in refining units, corrosive mechanisms such as produced by naphthenic acids evolves to attack the material. The corrosion resistance of steels that are used in these applications is improved by adding elements such as Cr and Mo, since these tends to form oxides that change the kinetics of corrosion and provide major stability to the material structure.
The temperature, velocity and naphthenic acids concentration effects in the corrosive mechanism of 5%Cr-1%Mo steel were studied in a dynamic autoclave by Electrochemical Impedance spectroscopy (EIS), Linear Polarization Resistance and Potentiodynamic Polarization Curves with an electrochemical cell of three electrodes: reference and counter electrode was made of Au and working electrode was 5%Cr-1Mo sample. The sample was exposed to mineral oil-naphthenic acids solutions to different concentrations (0.0-3.0 mg KOH/g) and 200 psi pressure. Contrary to the velocity effect, the temperature has a huge influence in the steel corrosion: to 180°C the steel exhibits lower corrosion rate, however, increasing temperature promotes the thermal composition of complex naphthenic acids, reflecting a reduction in resistance charge transfer between metal-electrolyte Rm/e, increasing the corrosion rate. Moreover, the temperature is closely related to the concentration acid effect, since the kinetics of corrosion changes significantly when the system is subjected to higher temperatures.
These results were complemented with surfaces characterizations by Scanning electron microscopy and dispersive X-ray analysis (SEM/EDX) and were observed major attacks on steel to higher temperatures. Moreover, the electrolytes were characterized by Fourier transform infrared spectroscopy (FTIR) and mass spectrometry techniques.
Electrochemical Impedance Study on Dissolution of Cu-Zn Alloy in Fresh Water
Authors: Hoshi Yoshinao , Tabei Kozue , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

The brass (Cu-Zn alloy) is widely used for the water pipe of constructional plant and the joint of the device material. One of the corrosion problems of Cu-Zn alloy is the dezincing, which is the selective dissolution of Zn from Cu-Zn alloy. The fundamental studies of anodic dissolution of Cu-Zn alloy were reported by Pickering et al. (1-3). They indicated that a porous Cu-rich layer was formed on the surface of Cu-Zn alloy due to the preferential dissolution of Zn from Cu-Zn alloy. They proposed the two types of the dissolution mechanisms, which were simultaneous and selective. However, the stability of the Cu-rich layer formed on the Cu-Zn surface has not been clarified yet.
In the present study, the dissolution of Cu-Zn alloy in the fresh water was investigated by an electrochemical impedance spectroscopy (EIS). The measurement of the electrochemical impedance was performed by three-electrode system. The working electrode (0.785 cm2) was Cu-Zn alloy (Cu-35at%Zn) and the counter electrode was the platinum wire. The KCl-saturated silver/silver chloride electrode (SSE) was used as the reference electrode. All the potentials in this study were referred to SSE. In order to investigate the stability of the Cu-rich layer formed on the surface of Cu-Zn alloy, the formation of the Cu-rich layer was conducted as follows. The Cu-Zn alloy (Cu-35at%Zn) was abraded by #1200 emery paper under running water. Then, the galvanostatic polarization of Cu-Zn alloy was measured at 1.0 mA/cm2 for 24 h. The electrolyte solution was 0.5M NaCl containing 5mM NaHCO3. The temperature of the electrolyte solution was keep at 60 oC by thermostatic bath.
The impedance spectra of the Cu-Zn alloy before and after the formation of Cu-rich layer on the surface of the Cu-Zn alloy were measured to examine the stability of the Cu-rich layer. In addition, the results of the rest potential and the anodic polarization curve were also discussed in the present study.
Reference
1. H. W. Pickering and C. Wagner, Journal of the Electrochemical Society, 114, 698 (1967).
2. H. W. Pickering, Journal of the Electrochemical Society, 115, 143 (1968).
3. H. W. Pickering and P. J. Byrne, Journal of the Electrochemical Society, 116, 1492 (1969).
Study of the Oxygen Reduction Reaction on the Coupled Galvanic Carbon Steel - Stainless Steel
Authors: Pérez-Quiroz José Trinidad , Genescá Llongueras Juan , Pérez-López Tezozomoc , Rendón-Belmonte Mariela , Terán-Guillen Jorge , Martínez-Madrid Miguel 
Published: February 2020

The main objective of this work is to study the electrochemical behavior of galvanic coupling between carbon steel, CS, and stainless steel, SS, in an alkaline environment simulating the conditions prevailing in a repaired structure in which stainless steel rebar’s will be an option. Previously research conducted in different parts of the world on this subject reach agreement with the fact that AISI 304 SS and 316 SS embedded in concrete offers high corrosion resistance in aggressive environments but only for the case of new structures, and no further explanation has been given on the behavior of SS when in contact with CS. Galvanic coupling between these two metals should increase the corrosion process of the more anodic, CS in this case, but this phenomenon does not occur in practice.
Galvanic coupling was investigated by means of the electrochemical coulostatic technique. Tests performed allow determining the Tafel slopes of anodic and cathodic processes. The Tafel slope values obtained show that the process is being controlled by the reduction of oxygen, O2 in the environment where the samples were placed. On the basis of these kinetic parameters, a mechanism for the corrosion process is proposed in which the rate determining step would be O2 mass transfer process. The diffusion of O2 would take place through a formed oxide film, passivating in nature. Due to the formation of this oxide film, the cathodic oxygen reduction reaction, ORR, on stainless steel surface would be very slow. The high polarization of ORR rate would be the factor controlling the whole process, then minimizing the risk of damage by galvanic corrosion, demonstrating the feasibility of using stainless steel in the repairing of concrete structures.
Microstructural and Electrochemical Characterization of Ti6Al4V Alloy
Authors: Flores-Álvarez José Fernando , Rodriguez-Gomez Francisco Javier , Onofre-Bustamante Edgar , Roncagliolo Barrera Paola 
Published: February 2020

The present work is an electrochemical study of Ti6Al4V alloy and TiO2 films obtained by thermal oxidation technique, and the use of cerium salt as a corrosion inhibitor. The electrochemical characterization was performed in phosphate-buffered saline (PBS) solution using the techniques of linear polarization and electrochemical impedance spectroscopy, and present phases’ characterization technique by scanning electron microscopy (SEM).
The protective capacity against corrosion of films using heat and cerium salt as corrosion inhibitor depends on the thickness of the oxide layer formed on the surface.
Blanks and thermally oxidized at 700 ° C for one hour and cooled in the oven for 24 hours samples, and samples heat treated + chemical conversion treatment with cerium 0.01 M can be ranked as follows according to their anticorrosive capacity: Ti6Al4V alloy <Ti6Al4V sample heat treated at 700 ° C <Ti6Al4V sample thermally + chemical conversion treatment treated with 0.01M cerium.
Passivation Magnesium in Phosphates for Its Application As Biomaterial
Authors: Ramírez Herrera José Manuel , Rodrígez Gómez Francisco Javier , Galicia Aguilar Gonzalo 
Published: February 2020

Magnesium is potentially useful in biomaterial application. However, the corrosion rate of this metal is so high that its degradation occurs before the end of the healing process; for that reason, there are some researches for alloys as AZ31 and AZ91, as well as some treatments were applied to these alloys expecting a decreasing in the corrosion rate. The aim of this work is to decrease the corrosion rate and find a different material from the AZ alloys, for that reason we performed a chemical passivation of magnesium. We got this passivation through the immersion of the specimen in a phosphates solution. These passivations were evaluated with electrochemical techniques in Kokubo’s solution (SBF) and results were compared with not passivated magnesium and AZ31. Open circuit potential, EIS, polarization curves were carried out in order to evaluate passivation.

The material was chemically characterized by using atomic absorption, while the surface was analyzed before and after the techniques by Scanning Electron Microscope (SEM).
All experiments were realized at room temperature conditions (≈22°C=71.6°F); the surface of the probe was prepared with sandpaper: 240, 320, 400, 600, 1200, 1500 and finished with an alumina 0.3 m polish in order to ensure an homogeneous surface. The chemical treatment was performed at room temperature and by immersion, the samples remains in the solution for 24 hours.

Through the electrochemical techniques performed in this study, a decrease in corrosion rate was reported when the samples were passivated with the phosphates, this effect was observed in Fig. 1. This figure shows the polarization curve of magnesium, AZ31 and their passivation. The corrosion potential is different in each case, the Tafel slopes are also roughly different, these differences are important because it means that the corrosion rate was modified. This modification of the corrosion rate can be corroborated with Fig. 2 that shows a higher impedance in the case of passivation compared with the magnesium.
Evaluation of an Imidazoline in Simulated Atmospheric Conditions as Corrosion Inhibitor through Electrochemical Noise
Authors: Roncagliolo Barrera Paola , Flores-Álvarez José Fernando , Rodriguez-Gomez Francisco Javier 
Published: February 2020

This work presents electrochemical noise measurement results from assessment of 2-methyl-2-imidazoline as inhibitor on a 1018 steel, at different relative humidity, categorized according to ASTM E 104 85.
A modified steel plates atmospheric corrosion probe (MECA) was used in order to measure potential and current noise time series; by using MECA, atmospheric corrosion rate could be determined, even if humidity was low.
Imidazoline is widely used in petrochemical industry as a corrosion inhibitor, so that was the reason for studying the behavior of this inhibitor in other corrosive processes as in the packaging or protection of metals exposed to atmosphere.
Spectral and statistical analysis of the noise data was carried out; after that, polarization curves were conducted to validate the information from noise and the use of MECA monitor. From the results, it was established that 2-methyl-2 imidazoline decreasing anodic potential and modifies the double layer adsorption.
The use of MECA monitor was validated, founding that records were reliable for electrochemical measurements of atmospheric corrosion.
Dissolution Mitigation of Alloy 690 By Electrochemical Surface Modification
Authors: Kim Kyung Mo , Shim Hee-Sang , Seo Myung Ji , Hur Do Haeng 
Published: February 2020

Metal oxide particles and metal ions are released from the inside surface of steam generator (SG) tubes in operating nuclear power plants. These corrosion products are transported into the core, forming a crud on fuel cladding. The composition of the fuel crud consists mainly of nickel ferrite, and it indicates that the primary source is the nickel element in SG tube materials. A higher crud buildup might cause an increase in radiation dose rate and axial offset anomaly (AOA). The metal ion release property is affected by water chemical conditions, and metal surface states such as the roughness and residual stress (work hardening).
In this work, the metal surface modification technique for reducing the metal ion release is investigated using an electrochemical polishing method and is evaluated with micro hardening on the surface layer.
The corrosion tests were performed using commercial alloy 690, which was heat processed by two steps, mill annealed, and thermal treated. The electro-polishing (EP) process was applied by ElectoMet® 4 (Buehler Co, IL). The specimen used a tube shape of 19.05 mm outside diameter, and was electro-polished on the inside surface. After the EP process, the surface morphology and roughness was investigated by field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM).
The corrosion test environment simulated the primary water chemistry in PWRs. The temperature and pressure were maintained at 330oC and 150 bars during the experiments. The condition of the test solution was 2 ppm lithium (LiOH) and boron 1,200 ppm (H3BO4), 35 cc/kg (STP) dissolved hydrogen and 10 ppb dissolved oxygen.
The metal ion release rate was evaluated using a gravimetric analysis method using a two-step alkaline permanganate-ammonium citrate (AP/AC) descaling process.
The change in the surface morphologies of the corrosion products is not remarkable, while the release rate is lower by a factor of two when the surface was modified using the appropriate electrochemical polishing method. The metal ion release rate is mainly dependent on the surface roughness as the function of EP time and electrolyte composition. The specimen which had EP time for 8 minutes showed most improvement of metal ion release rate.
Development of a Novel, Environmentally Compliant Magnesium Coating System for Corrosion Protection of Magnesium Alloys
Authors: Nunez Michael , Naccarelli Anthony , Sikora Elizabeth , Shaw Barbara A 
Published: February 2020

Due to its low density and good mechanical properties, Mg and its alloys are very attractive materials for aerospace applications. However since Mg is the most electrochemically active structural metal, protecting it from environmental degradation presents a real challenge. Corrosion of Mg alloys depends on their chemical composition and microstructure. The intermetallic phases formed during production processes are more noble than the Mg matrix and result in the establishment of microgalvanic cells within the Mg alloy; thus, accelerating the overall corrosion of the Mg. To shield Mg and its alloys from corrosive environments, their surfaces are usually protected by chemical and conversion inorganic coatings, sol-gel coatings, anodization, or thermal spraying. But one has to be aware that defects present in the coating or developed during operation often result in the formation of galvanic cells leading to accelerated corrosion of Mg component.
An ideal, effective coating should be able to simultaneously provide corrosion protection through: sacrificial anode-based cathodic protection, active corrosion protection to minimize corrosion at defects (for example by releasing active inhibitors), and formation of a protective barrier layer on the substrate surface. Producing a protective coating which could fulfill the above requirements is extremely challenging. For example, creation of sacrificial coatings for Mg substrate is not an easy task, because there are not many engineering materials more active than Mg alloys. However physical vapor deposition technology can be employed to produce anodic coatings capable of sacrificially protecting Mg alloy components.
Our preliminary results show that physical vapor deposition process indeed can produce thin films of Mg alloys with sacrificial properties. These thin films were tested in artificial sea water in ambient conditions:

Alloy

Form

OCP (V vs. SCE)

Corrosion rate, mpy

Pure Mg
bulk
-1.6
131.3

Thin film
-1.9
27.6

AZ31
bulk
-1.6
34.3

Thin film
-1.8
3.6

AZ91
bulk
-1.6
9.5

Thin film
-1.8
6.3

The electrochemical parameters show that thin films not only exhibit lower corrosion potential (on average lower by 200 mV) but also have lower corrosion rate. Obviously, the corrosion performance of the thin film is a function of the microstructure of the deposits and this in turn depends on deposition parameters. The key factors in deposition process which enable production of films with tailored properties will be discussed.
The Effects of Oxygen Concentration and pH on the Galvanic Protection of Tin
Authors: Geary Steven , McMurray Hamilton Neil , de Vooys Arnoud C.A. , Wint Natalie 
Published: February 2020

SVET is used to investigate rapid detinning processes affecting commercial tinplate (produced by TATA steel) in the malic acid solutions, commonly found in tinned food products. In malic acid concentrations ≥ 0.1 mol dm-3 tin was found to become sacrificial with respect to iron, reversing the polarity predictions on the basis of tabulated Eo values. The tin dissolution mechanism in aerated solutions is shown to be cathodically controlled by the mass transport of oxygen to the exposed steel cathode [1]. The sweeping removal of the tin coating is represented in Figure 1 which shows SVET-derived current density maps, the localised anodic dissolution of tin intensifies with an increasing cathodic steel surface area supporting the oxygen reduction reaction.
Particular emphasis is given to the effects in low partial pressures of oxygen replicating the conditions occurring inside a food can. A novel, Environmentally controlled Scanning Vibrating Electrode Technique (E-SVET) is described which allows the measurement of localised corrosion current flux under conditions of controlled oxygen partial pressure. Experiments undertaken using the E-SVET show that reducing the oxygen partial pressure significantly reduces the detinning rate due to the limited oxygen supply for the cathodic oxygen reduction reaction. Polarity reversal and oxygen reduction kinetics are confirmed using global electrochemical techniques such as RDE and OCP [2,3].
[1] S. Geary, H. N. McMurray and A. C. A. de Vooys. ECS Transactions, (2013), 50, p37-51.
[2] M. S. Abdel-Aal and M. H. Wahdan. British Corrosion Journal, (1988), 23, p25-28.
[3] V. Jovancicevic and J. O'M. Bockris. Journal of The Electrochemical Society, (1986), 133, p1797-1807.
Figure 1. 3D SVET-derived maps showing the distribution of normal current density J above a detinning 2.5gm-2 non-reflowed tinplate sample in 0.1 mol dm-3 malic acid at (a) 3 hours, (b) 3.9 hours and (c) 4.8 hours and (d) 5.1 hours of immersion.
Investigation of CdS Thin Films Deposition by the SILAR Method Using Cd(II) Organic Salt as Precursor
Authors: Tamasauskaite-Tamasiunaite Loreta , Simkunaite-Stanyniene Birute , Zieliene Albina , Naruskevicius Leonas , Selskis Algirdas , Norkus Eugenijus 
Published: February 2020

In the present study thin cadmium sulfide (CdS) films were prepared by means of the successive ionic layer adsorption and reaction (SILAR) method. Cadmium 2,4-pentanedionate and sodium sulfide precursors were used to prepare CdS thin films.
The morphology and composition of CdS thin films were characterized using Field-Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and X-ray Photoelectron Spectroscopy. The optical properties of CdS thin films deposited on the glass sheets were investigated by measuring optical absorbance in the wavelength range 300 to 800 nm.
The thin CdS films having a crystalline structure with CdS particles of ca. 20-80 nm in size were deposited on the glass sheet by the SILAR method. The data of optical properties of CdS films deposited with different thickness are compared and presented.

Acknowledgement

The work was carried out within the project VP1-3.1-ŠMM-08-K-01-009 that is partly supported by the National Programme “An improvement of the skills of researchers” launched by the Lithuanian Ministry of Education and Science.