bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Vapour Effects on Wustite Scale Growth at High Temperatures
Authors: Yin Huaying , Young David John 
Published: February 2020

High purity iron and a low carbon, low silicon steel were oxidised at temperatures of 800 to 1200oC, in atmospheres of N2-H2-H2O and N2-O2-H2O. Scales of wüstite grew at low oxygen potentials, and of FeO/Fe3O4/Fe2O3 at high potentials. In both cases, kinetics were parabolic after an initial transient period. The iron and steel behaved similarly in O2/H2O gases, but not in H2/H2O. Weight uptake kinetics for both metals were initially linear, changing to parabolic with time as diffusion slowed and became rate-controlling [1]. Iron generally reacted faster than steel, but eventually developed parabolic kinetics. The effect of p(O2) at fixed p(H2O) on kw
for iron and steel is seen in Fig. 1 to be functionally similar. However, whereas the oxidation rate of steel is strongly dependent on p(H2O), that of iron is not [2,3]. The Arrhenius plot in Figure 2 shows that activation energies for the two materials are rather similar at 157 kJ mol-1 for temperatures of 800 to 1100oC, but iron oxidises almost three orders of magnitude faster than steel. However, at 1200oC, oxidation rates are closely similar.
The predictions of the Wagner model of rate control by lattice diffusion of iron vacancies is shown to be quantitatively successful for reaction of pure iron in H2/H2O. The slower rates observed for steel are attributed to defect interactions with impurity species, perhaps including a hydrogen-bearing species. Gas composition effects on the parabolic rate constant, kw
, for steel can be described by the expression:
kw = A p(O2)1/4 + B p(H2O)1/2 (1)
where p denotes partial pressure and A, B are constants. A model based on simultaneous diffusion of singly charged vacancies on cation sites and hydroxyl ions on anion sites is shown to account for this relationship.
Scaling rates in O2/H2O also increased with water vapour level, a result attributed to gas phase transport within oxide pores which were present in the scales, but absent in wüstite grown in H2/H2O. Rates for iron and the steel were the same, in each case reflecting mainly the growth of a thick wüstite layer. The lack of impurity effects on the steel oxidation is attributed to the failure of hydrogen-bearing species to penetrate the outer layers of magnetite and hematite which form in these gases.

References

1. H. Yin, S.L.I. Chan, W.Y. D. Yuen and D.J. Young,
Oxid. Met.
, 77 (2012) 305-323.
2. H. Yin, W.Y.D. Yuen and D.J. Young,
Mater. Corros
., 63 (2012) 869-877.
3. H. Yin and D.J. Young,
Oxid. Met
., 79 (2013) 445-460.

Figure 1
Measurement of Cr Evaporation in Several Nickel Based Alloys at Moderate Velocities
Authors: Tylczak Joseph H , Holcomb Gordon R 
Published: February 2020

Chromium is the principle basis of corrosion protection in most moderate-to-high temperature oxidation resistant alloys. The loss of Cr from an alloy is significate in its expected operational lifetime, as its loss can lead to beak-way oxidation. Gas flow rate is an important parameter in the loss of Cr. Most laboratory Cr evaporation experiments have used relatively low gas flow rates. In this research the Cr loss rate was investigated at 760 °C, in an air plus 57 vol pct water environment with an apparent gas flow rate of 26.5 m·sec-1. This speed was achieved by spinning the samples on the end of a disc in a gas filled, heated retort. Since secondary alloy additions can have an effect on chrome activity and diffusion, three nickel based alloys with similar (~21 wt pct) Cr levels were investigated. The alloys chosen were HAYNES 230, 282, and Inconel 625. Moving and static samples (hung near the moving samples) were exposed for times up to 1000 hrs.
Samples were first measured gravimetrically and then the surfaces examined via SEM. Finally the samples were cross sectioned and examined via SEM with EDS to determine Cr depletion. Results show a noticeable difference for the IN 625 surface, as viewed via SEM, between the surface scale formed on the respective static and moving samples. The viewed surfaces of the HAYNES 230 and 282 samples did not show as substantial of a difference between each’s respective static and moving sample. The moving IN 625 sample showed both higher mass loss and deeper Cr depletion than the static sample. The HAYNES 282 showed the least mass change, both in the static and moving conditions. At 1000 hr the HAYNES 282 had near zero total mass change while the static sample had some mass gain. At 1000 hr both HAYNES 230 and the IN 625 moving samples had gained about twice as much mass as their respective static samples. Analysis showed the Cr depletion was deeper in all the moving samples, as compared to their respective static ones. The IN 625 had the deepest Cr depletion, followed by HAYNES 282, and then the HAYNES 230.
Nano-Structured Coatings for Supercritical Steam Turbines Application: High Temperature Corrosion Studies By TG-Mass Spectrometry
Authors: Perez Trujillo Francisco Javier , Mato Maria Sonia , Illana Andrea , Lasanta Isabel , Castañeda Saul , Alcala German , De Miguel Teresa 
Published: February 2020

Supercritical Steam Turbines will be operated at 3.00 Bar and 650 C. It meas that the ferrritic substrate steels must be coated in order to resist the oxidation processes that appears in those operation conditions. At the present time, there are metallic coatings canidates that are one option for this problem, but a new way to obtain better performances is the application of nano-structred coatings composed by metallic nitrides on ferritic steels such as P92.
Among the different processes, an important degradtaion process that appeaars at this temperature is the volatilization process; in order to analyse a TG-Mass spectrometry set up is used to monitor the vlatilization of coatings. A comprehensive analysis will be perform, jointly with gravimetric tests.
A detailed characterization by SEM, GD-Analysis abd XR-Difraction will be show.
A complete degradation mechanism in comparison with metallic-microestrucrured coatings will be povided.
Corrosion Investigation of Ni-Free Nitrided Stainless Steel Material As Bipolar Plate for Polymer Electrolyte Fuel Cell
Authors: Shironita Sayoko , Yu Yang , Nakatsuyama Kunio , Souma Kenichi , Umeda Minoru 
Published: February 2020

Bipolar plates are particularly required mechanical strength and corrosion resistance for automobile application of polymer electrolyte fuel cell (PEFC). Thin metallic bipolar plates enable to realize small-size and light-weight PEFC stacks. However, there is some problem for cost, durability, and so on. In this study, we report an improvement of the corrosion resistance of Ni-free stainless steel (SUS445) by a nitriding heat treatment.
Nitriding heat treatment of Ni-free stainless steel (SUS445) was performed using a vacuum furnace under nitrogen atmosphere at 1473 K. Electrochemical measurements were carried out using a three-electrode electrochemical cell having a Pt counter electrode, an Ag/Ag2SO4 reference electrode, the SUS445 and the nitrided stainless steel (SUS445N) as a working electrodes in Ar-saturated 0.5 mol dm-3 H2SO4 solution at room temperature. Linear sweep voltammogram was obtained from a rest potential to 1.1 V vs. SHE at a sweep rate of 0.33 mV s-1.
Linear sweep voltammograms of SUS445, SUS445N, and SUS316 are shown in Figure 1. The voltammogram of SUS445 has current peak corresponds to a formation of passivation layer at -0.2 V vs. SHE. The onset potential of the SUS445N voltammogram shifts toward the positive direction and there is no current peak of the passivation layer formation. The current density of SUS445N is one order of magnitude lower than that of SUS445 and SUS316. It is found that the corrosion resistance of SUS445 improved by the nitrogen heat treatment. Moreover, PEFC operation test was performed using SUS445N bipolar plates and graphite one for a comparison. The two cell voltage at 0.25 A cm-2 were almost the same up to 2500 h power generation. Therefore, the Ni-free nitrided SUS445 exhibited a high durability as the bipolar plate of PEFC.

Figure 1
Dictating Organolead Perovskite Nanostructure Size Using Silicon Nanotube Templates
Authors: Coffer Jeffery L , Gonzalez-Rodriguez Roberto , Arad-Vosk Neta , Rozenfeld Naama , Sa'ar Amir 
Published: February 2020

A class of alkyl ammonium lead halide structures that readily crystallize as perovskite phases of the generic formula CH3NH3PbX3 have been discovered, and their relative ease of crystallization and formation into robust films have led to the development of an exciting new class of photovoltaic and lasing platforms. To our knowledge, however, synthetic methods that permit an evaluation of the fundamental size dependent properties with the requisite level of control of any of these perovskite structures have not yet been achieved. The key element to achieving feature size control in the synthesis of these perovskite phases is the use of hollow semiconducting silicon nanotubes as templates for perovskite growth; i.e. viewing the nanotube interior as a nanoscale reaction vessel. We have recently reported a facile strategy for the formation of SiNTs of a broadly tunable inner diameter, as well as Si wall thickness. These nanotubes are currently under evaluation for a diverse range of additional uses, such as loading with magnetic nanostructures, drug loading and subsequent delivery, Li storage and discharge phenomena associated with battery technology, etc. In principle, these nanotubes permit structural control of perovskite width through nanotube inner diameter.
In this work, we describe the formation of methylammonium lead iodide nanostructures inside porous silicon nanotubes with a wall thickness of 10 nm and possessing inner diameters of either 70 nm or 200 nm. After structural characterization, the photophysical properties of these perovskite nanostructures, in terms of optical absorption and photoluminescence as a function of temperature, are evaluated. Spectroscopic comparisons with relatively larger one-dimensional microwires of the same composition are also carried out. We seek to interrogate not only the presence of size dependent shifts in absorption/emission features associated with a given perovskite structure, but also the effects of physical confinement on possible size-dependent phase behavior of these one dimensional semiconductors.
Formation of Self-Organized Nanohole Arrays on Stainless Steels
Authors: Tsuchiya Hiroaki , Hamada Shoken , Yamada Natsuko , Fujimoto Shinji 
Published: February 2020

Self-organized nanotubular and nanoporous oxide layers have been reported on a variety of valve metals and their alloys by anodization in fluoride-containing electrolytes due to a wide range of their applications. In addition to valve metals and alloys, the formation of the porous oxide layer is achieved also on stainless steel in a fluoride-containing electrolyte[1]. Nanotubular oxide layers have been formed not only in fluoride-containing electrolytes but also in chloride or perchlorate containing electrolytes. In the case of valve metals, the formation of bundles of nanotubes are fabricated on Ti and W in chloride or perchlorate containing electrolytes whereas the highly ordered nanohole arrays consisting of circular dimple are obtained on stainless steels in perchlorate containing electrolytes[2, 3]. In the present work we examine the formation of nanohole arrays on various stainless steels and report how chemical composition of the steels affect the morphology of nanohole. In addition, the other properties of the stainless steel with nanohole arrays are briefly presented.
References
[1] K. Kure, Y. Konno, E. Tsuji, P. Skeldon, G.E. Thompson, H. Habazaki, Electrochem. Commun. 21 (2012) 1.
[2] V. Vignal, J.C. Roux, S. Flandrois, A. Fevrier, Corros. Sci. 42 (2000) 1041.
[3] H. Tsuchiya, T. Suzumura, Y. Terada, S. Fujimoto, Electrochim. Acta 82 (2012) 333.
Modeling of Porous Metal Oxide Layer Growth in the Anodization Process
Authors: Habera Michal 
Published: February 2020

Most of the works on nanotubes growth are oriented on exploring suitable setups for optimal growth for the structures. Substantially less interest is devoted to first principles based mathematical modelling of the growth. We present a simple mathematical model of porous metal oxide layer growth in the anodization process.
The mathematical model is essentially the model used by [Sample, Golovin: Formation of porous metal oxides in the anodization process, Phys. Rev. E 74, 2006]. The dynamics of the system is determined by the solution of the continuity equation for the electric current density, while the boundary conditions for the overpotential are given by the Butler-Volmer relation.
The arising system of partial differential equations is solved using the finite element method. Unlike in the other works, the continuity equation for the electric current density is solved not only in the oxide layer, but also in the metal and the electrolyte. The positions of the interfaces are not known a priori and must be found in the process of the numerical solution of the problem.
The core technical difficulty is the tracking of the metal/oxide and oxide/electrolyte interface. This issue is addresed via the application of the level-set method. The main benefit of using the level-set method is that it can easily handle topology changes and that the computation is done on a fixed mesh.
Another important ingredient of the developed numerical scheme is that the problem is solved using the mixed formulation. The mixed formulation allows one to succesfully handle the boundary condition arising from the Butler-Volmer relation even in the level-set setting. It is shown that the chosen methodology correctly captures the discontinuities of the electric potential at the interfaces.
The advocated numerical scheme has been implemented in FEniCS (software for the automated solution of differential equations by finite element methods). Results of the simulations with the physical parameters corresponding to the growth of aluminium oxide layer are presented.
The computational methodology based on the level-set method and on the mixed formulation can be easily applied in two dimensional as well as in three dimensional setting. The successfully developed method for the interface tracking which is the core technical difficulty in the modelling of oxide layer growth allows one to think about further extensions of the model. In particular the flow in the electrolyte, the deformation inside the oxide layer as well as surface tension effects could be possibly numerically simulated in the future.
Influence of Corrosion Product on Corrosion Behavior of Carbon Steel in Atmospheric Environment
Authors: Shinoda Honami , Katayama Hideki , Hoshi Yoshinao , Shitanda Isao , Itagaki Masayuki 
Published: February 2020

Atmospheric corrosion proceeds under thin water film, and it is affected by many environmental factors such as temperature, relative humidity, rainfall, deposition of airborne sea salt. Most of the previous study of atmospheric corrosion of carbon steel has been focused on the corrosion behavior in initial corrosion process. However, corrosion products are formed on the surface at an early stage in case of carbon steels. Thus it is important to clarify the influence of corrosion products on atmospheric corrosion behavior.. While corrosion products may easily lead to wet condition with absorption of moisture, it is reported that corrosion products inhibit the corrosion physically or chemically. In this study, we focus on dew condensation which occurs on the surface of carbon steels with rust layer.
The electrodes with corrosion products were prepared by wet/dry cyclic corrosion test. The remodeled concentric corrosion sensor was used as the electrodes. The temperature of electrode materials can be controlled from the backside of electrode because the backside of the remodeled sensor is exposed to atmosphere. The corrosion test was carried out in a chamber at 25℃ and 60％RH by adding the droplet of 0.1M NaCl solution or distilled water. During the corrosion test, the corrosion rate of the electrode was monitored by electrochemical impedance method. The electrode covered with corrosion products was cooled with a cooling equipment in the chamber at 25 ℃ and 60 ％ RH in order to measure the dew point. The dew point was evaluated by measuring solution resistance using electrochemical impedance method. The dew point of the electrode before corrosion test was measured. The solution resistance dropped sharply to a low value at around 17 ℃. The dew point was calculated at 17℃ under the 25℃ and 60％RH from the curve of saturation water vapor pressure and Tetens’s equation, indicating that the experimental and calculated values are in good agreement. The amount of corrosion products increased with an increase of the cycle number. The solution resistance of the electrode after corrosion test went down at the temperature higher than the calculated value.
In addition, the deposition of corrosion products occurred an increase of the dew point of the electrode.
This is attributed to the diameter of pore in rust layer. It is known that equilibrium water vapor pressure in the crevice increases with a decrease of the crevice size. This means that the humidity in crevice increases in comparison with relative humidity of atmosphere. It is predicted the deposition of corrosion products leads to the formation of smaller size of pores. The chloride ion is included in the rust layer, and thus the water absorption of chloride ion occurs even at higher surface temperature.
The Effect of Carbon Dioxide Pressure in Carbon Steel Corrosion in 5 Wt.% NaCl Solution Using Flow Loop
Authors: Kim Hyoung Chan , Lee Sang Joon , Cho Seong Jun , Lee Ju Dong , Lee Young Cheol , Moon Hyeong Soon , Park Kyung Tae 
Published: February 2020

The pipelines transport a raw, unrefined well stream, usually consisting of a multiphase flow of gas, oil and water contained carbon dioxide, hydrogen sulfide and chlorides at elevated temperatures. Internal corrosion is the important factor affecting the reliability and longevity of subsea oil and gas pipelines in the oil and gas field. In the pipeline design, the measurement of corrosion rate was evaluated under similar corrosion environments using flow loop.
The flow loop installed at KITECH located in Korea was made of UNS 31603 with internal diameter 1 inch and corrosion tests can be performed up to 7 m/s liquid velocity and up to 12 m/s gas velocity under maximum pressure 10 MPa. The flow loop system was comprises of a progressive cavity pump, separator, corrosion test section and corrosion monitoring equipment such as electrical resistance probes, linear polarization resistance probes. Corrosion inhibitor performance test, gas hydrate test etc. can be conducted with the system.
Material of the coupon was API 5L X52 and weight loss coupon method was adopted based on NACE Standard RP 0775-2005. Measurement of corrosion rate was conducted under test conditions, 0 and 0.5 MPa, dissolved oxygen concentration less than 10 ppb, temperature 313 K, for 24 hours in NaCl 5wt. % solution at the velocity of 3 and 4 m/s respectively.
The test results showed that corrosion rate increased at higher flow rate and the predominant factor of corrosion was not chloride concentration but pH of the internal liquid of the flow loop.
Hydrogen Entry into an AISI 4135 High Strength Steel in Tribocorrosion Environment
Authors: Doi Kotaro , Akiyama Eiji , Hayakawa Masao 
Published: February 2020

High strength steels are susceptible to hydrogen embrittlement which decreases long-term reliability. Suspension coil springs for automobile are made of high strength steel and have high tensile strength. The end turns of springs are considered to be suffered from both corrosion and wear and the synergistic effect of them, tribocorrosion. To examine the possible enhancement of hydrogen entry by tribocorrosion, we recently investigated hydrogen entry in a simulated tribocorrosion environment, and found that the amount of entered hydrogen in tribocorrosion environment was larger than that in simple corrosion environment in a NaCl solution. For further understanding of the role of wear and corrosion on hydrogen entry into steels, hydrogen entry caused by tribocorrosion and in corrosion in a low pH solution has been investigated in this study. The effects of low pH solution, corrosion and wear on the amount of hydrogen entry will be discussed in our presentation.
Tribocorrosion test was conducted using samples of an AISI 4135 with 1300 MPa of tensile strength with 20 mm diameter and 5 mm thickness. In the tribocorrosion test, pin-on-disk type wear apparatus equipped with a cell containing corrosive solutions was used and the sample was worn by a SiC ball with 10 mm diameter in a NaCl solution or a NaCl+H2SO4 solution for 48 h. The rotation diameter of SiC ball was 10 mm and the rotation speed was 150 rpm. The tests were conducted at room temperature. For comparison, corrosion test without wear was also conducted by samples immersion in the NaCl solution or the NaCl+H2SO4solution. Changes in pH of solution were measured during the test. After tribocorrosion test and corrosion test, the amount of hydrogen in the sample was measured by means of hydrogen thermal desorption analysis.
The result of hydrogen thermal desorption analysis showed that the amount of entered hydrogen in the worn sample was lower than that of the immersed sample in the acidic NaCl+H2SO4 solution, though the amount of entered hydrogen in the worn sample was larger than that of the immersed sample in the neutral NaCl solution as mentioned above. This is because that pH of the acidic NaCl+H2SO4 solution during the tribocorrosion test increased with time.