Selective oxidation of Fe2MnxSi alloys with various Si contents annealed in a gas mixture of H2/H2O (p(O2) = 6.5×10−25 bar at 700 °C) for 2 h was investigated. The oxidation kinetics of all the alloys followed linear growth, indicating that most likely oxygen uptake was the rate-determining step. The addition of Si into Fe2Mn eliminated the formation of the ridge-like MnO at the surface, mainly on

The corrosion behavior of as-cast and extruded Mg4Zn0.2Sn (wt.%) alloys was comprehensively compared in 0.5 wt.% NaCl solution. Microstructure and surface chemistry related corrosion performance has been revealed. Zinc-supersaturated solid solution is formed around the intermetallics in the as-cast alloy, but zinc alternately segregates between the α-Mg matrix in the extruded alloy. According to Scanning

Long-term corrosion behavior of T91 ferritic/martensitic steel in oxygen-doped flowing Pb–Bi eutectic is investigated by exposure for up to 20,000 h at 400 °C, 2 m/s and 2 × 10−7mass% dissolved oxygen. The corrosion phenomena and kinetics of interaction are characterized qualitatively and quantitatively. The steel shows major oxidation resulted in the formation of a bilayer Fe3O4 / Fe(Fe,Cr)2O4 scale

Electrochemical techniques were used to investigate the erosion-corrosion of titanium in simulated acidic mineral leaching slurries. Erosion-corrosion of titanium was caused by solid particle impingement. Electrochemical noise revealed that solid particle impacts resulted in localised fracture of the passive film, and erosion-corrosion of titanium proceeded in the form of current transients. As conditions

WC-Co-based cemented carbides with cubic carbides (Ti,W)C/TaC were prepared and the early oxidation behavior of their surface layers was investigated. Different carbides exhibit independent oxidation processes and selective oxidation behavior. The solid solution containing Ti slows the oxidation process due to its high stability. In addition, an oxidation stage model was established to describe the

Corrosion tests of Ni-30Cr alloy were performed in three simplified soda-silicate and borosilicate melts in order to follow the evolution of the protective chromia layer. A complete identification of the corrosion mechanisms enables the establishment of a kinetic model based on the oxide formation and dissolution rates. The dissolution kinetics is strongly dependent on the chromium solubility limit

This research concerned the corrosion behaviour of low-carbon steel reinforcements in Portland cement, alkali-activated slag, and alkali-activated slag-steel slag mortars under simulated marine environment. Electrochemical measurements were used to monitor the corrosion process. The results showed that the steel reinforcements in alkali-activated mortars showed higher corrosion resistance under simulated

The effect of reactive air aluminizing (RAA) on the high temperature oxidation behavior of the H230 superalloy is studied at 850 °C for 600 h. Mass gain values are measured and microstructure is studied by XRD, SEM, and EDX. Post oxidation mass gain for the aluminized H230 is reduced compared to wrought H230. The RAA process lead to formation of a three-zone diffusion coating with dominant β-NiAl in

The electrochemical performance of a new 6% Cr steel was investigated intensively by means of a broad variety of electrochemical methods (EIS, CV and CPP) and surface characterization techniques (AFM, XPS, EPMA and ESEM/EDS) in simulated concrete pore solution (SCPS) with chlorides. Improved corrosion resistance of 6% Cr steel in SCPS was established by the protective passive film, the high pitting

The corrosion behavior of VM12, Sanicro 25, and Inconel 617 in supercritical carbon dioxide at 600 °C and 15 MPa was investigated. Chromia-forming alloys Sanicro 25 and Inconel 617 had better corrosion resistance than VM12, which formed Fe-oxide rich scales on its surface. In all materials, internal carburization zones were found underneath the oxide scales. Based on the results that the growth of

In this study, we characterized interfacial mechanisms to better understand the active–passive state for a laser powder-bed-fused (L-PBF) AlSi12 alloy. We compared the additive manufactured microstructures obtained via the L-PBF process vs. the traditional casting method with respect to their influence on corrosion properties. Corrosion resistance was assessed by the damage mechanism based on the corrosion

A simple modification using adsorbed benzotriazole is shown to significantly improve the performance of zinc phosphate corrosion inhibitive pigment in slowing rates of organic coating failure. The novel inhibitor, ZnPhos-BTA, is dispersed within a model coating and the scanning Kelvin probe (SKP) is used to monitor corrosion driven cathodic coating delamination from hot dip galvanized steel (HDG).

Corrosion tests were performed on newly developed alumina-forming austenitic (AFA) steels in stagnant lead bismuth eutectic (LBE) with saturated and low oxygen concentrations at 450 ℃ for 430 h. The steels exhibited enhanced corrosion resistance to the LBE environments with the increasing of Al content. A continuous and protective Al-rich oxide scale formed on the steel specimens that were exposed

Internal oxidation of Ag-xIn alloys (x = 10, 13, 16 at%) was studied in an air atmosphere at a relatively low homologous temperature (240 °C), where lattice diffusion is negligible. After exposure, metallic Ag nodules were present on the surfaces of all alloys, expelled to relieve stress due to internal oxidation, confirming that such coarse morphologies can be produced by short-circuit transport.

The purpose of this study is to evaluate the corrosion resistance of weld metal by electrochemical methods and discuss the relationship between microstructure and corrosion resistance. Intergranular and pitting corrosion resistances were measured using electrochemical potentiokinetic reactivation (EPR) test and pitting potential measurement respectively. The reactivation ratio and pitting potential

High temperature stability (1100-1500 °C) and oxidation behavior at 1500 °C of the SiOC/HfO2 ceramic nanocomposite were investigated in air. Consumption of free carbon in bulk dominated the thermal stabilities at below 1200 °C. Whereas, the continuous cristobalite scale, rather than HfSiO4, was responsible for the improved oxidation resistance at exceeding 1200 °C. At 1500 °C, HfSiO4, with maximum

The effect of high temperature on the corrosion behaviour and passive film composition of 316 L stainless steel in high H2S-containing environments was investigated. The results showed that high temperature promoted the formation of thicker but more defective passive film. The dominant composition of passive films converted from Fe, Cr to Ni, Fe as the temperature increased from 30 °C to 130 °C, due

Formation of corrosion products on zinc was investigated with in-situ Raman and FTIR when exposed to wet supercritical carbon dioxide (scCO2) and subsequent depressurization. Zinc oxide (ZnO) and smithsonite (ZnCO3) formed on zinc in scCO2. The dissolved water precipitated as liquid water in the reaction cell during depressurization. Formation of ZnO, ZnCO3 and a needle-like zinc hydroxy carbonate

The low pH of magnesium potassium phosphate (MKPC) has raised concerns over its capability to protect reinforcing steel. The passivation of mild steel in MKPC pore solutions was investigated in this study via electrochemical measurements, XPS and Raman spectroscopy. Results show that the passivity of mild steel in MKPC was comparable or even better than that in Portland cement. Although the passivity

A native passive film on 25Cr-7Ni super duplex stainless steel was analyzed using synchrotron hard X-ray photoemission electron microscopy, focusing on variations between individual grains of ferrite and austenite phases. The film consists of an oxide inner layer and an oxyhydroxide outer layer, in total 2.3 nm thick. The Cr content is higher in the outer than the inner layer, ca. 80 % on average.

Metal dusting resistance of Inconel 625 alloy obtained by laser beam melting (LBM), compared to wrought alloy 625 was assessed during 9 500 h at 610 °C. Whatever the manufacturing process, the mass variations were very small when the systems were ground thanks to the formation of a uniform protective chromia layer. However, the high surface roughness was shown to be detrimental as the waviness favoured

Sulfate-reducing bacteria (SRB)-induced corrosion of 2205 duplex stainless steel (DSS) was investigated via novel high-resolution characterization. After 28 days of immersion, the corrosion rate of coupons in the SRB-inoculated medium was 10 times higher than that of coupons in the sterile medium. Corrosion products were absent from the top-part of the biofilm where acidic −COOH was present, which

The B-modified SiC/HfC-SiC composites were prepared by the combination of precursor infiltration and pyrolysis (PIP) and chemical vapor deposition (CVD) methods. The microstructure, cyclic ablation and bending strength tests of the SiC/HfC-SiC composites with and without B were investigated. The results showed that the B-modified composites had a better cyclic ablation resistance than that of the composites

Graphene is cathodic to most metals and can cause promoted corrosion to metals. Herein, we demonstrate that tuning oxygen reduction reaction (ORR) activity of graphene through fluorination modification is an effective strategy that can inhibit the corrosion-promotion activity of graphene. It is revealed that the cathodic ORR activity of partially fluorinated graphene (PFG) decreases with the increase

This paper studied the microstructure and corrosion behavior of Mg-xSc binary alloy (x = 0.1–1.5 wt.%) sheets. Sc has a significant effect of refining grains of Mg. The Mg-Sc binary alloys had a single-phase microstructure for Sc concentrations between 0.1−0.3 wt.%, while there were Mg-Sc precipitates for higher Sc concentrations. The Sc additions obviously improved the corrosion resistance of pure

This work describes 2-mercaptobenzothiazole (MBT) and 2-mercaptobenzimidazole (MBI) adsorption on Cu(111) by a systematic DFT study. Whatever the surface coverage of the adsorbed molecule, the adsorption is favored when the exocyclic sulfur atom is unprotonated (i.e. thione and thiolate forms). At low molecular density, the molecules adsorb forming a Cu-S(exo) and a Cu-N bond, and the adsorption energies

Metal salt films play a critical role in high rate dissolution processes such as within an active pit. However, structural and compositional characterization of salt films is challenging owing to the dynamic nature of the dissolving interface. Here, the salt film formed on SS304 one-dimensional artificial pit surface was preserved by flash freezing and characterized using cryo-based focused ion beam/scanning

Graphene sheets containing porous polyhedral oligomeric silsesquioxane (POSS) framework were synthesized as nanocontainer for self-healing organic coating. The corrosion inhibitor of benzotriazole (BTA) was loaded into the porous graphene sheets and then imbedded into epoxy coating to form composite coating. Results showed that the composite coating exhibited excellent self-healing capacity due to

Cr coatings have been deposited on the outer surface of zircaloy-4 tube with well control of thickness variations along the tube axis. A series of samples have been oxidized in high temperature steam environment at 1200 °C for different durations. Cr2O3 layers are formed on the surface of the Cr coatings after high temperature oxidation, however, we have found that the thickness of the Cr2O3 layers

Creep tests were performed for a nickel-base alloy, Ni-16Cr-9Fe, in air, atmospheric CO2, and supercritical-carbon dioxide (S-CO2) at 650 °C. Creep rupture lives in S-CO2 were shorter compared to air and CO2 environments, and the difference was greater at lower applied stress. Combined effects of applied stress and high pressure caused the formation of thicker oxides, which were subjected to extensive

The oxidation mechanism and products of U3Si2 accident tolerant nuclear fuel in flowing air up to 750 °C is reported. Differences between observed and theoretical mass gains for complete oxidation is due to un-oxidised Si that forms nano-crystalline regions of Si. Some Si rich regions are protected by the formation of UO2, which is thermodynamically preferential to oxidise before Si. The UO2 is further

To improve the hot corrosion resistance, thickness controllable SiO2 coating was electrodeposited on TiAl alloy. The hot corrosion behavior of the specimens contaminated with 75 wt.% Na2SO4 + 25 wt.% NaCl salt mixture was investigated at 700 °C. Results showed that the generation of compact amorphous SiO2 embedded with Na2Si4O9 and cristobalite was responsible for the enhanced hot corrosion resistance

The protection performance of a submerged sacrificial anode coupled with conductive carbon fiber mortar on rebar in mortar column in the splash zone is investigated here. The results indicate that rebar in splash zones can be effectively protected by the submerged sacrificial anode-conductive mortar system. Compared with magnesium alloy anodes, aluminum alloy anodes are more suitable for the system

A 1000 -h corrosion experiment of 316H stainless steel at 700 °C investigated the role of metal fluoride impurities CrF2 and FeF2 in LiF-BeF2 (66-34 mole %) (FLiBe) salt. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) demonstrated the ability to measure changes in the concentration of these fluorides in FLiBe salt. Cyclic voltammetry (CV) showed the potential for real-time quantitative

Surface analytical techniques were used to characterize the chemical composition and the thickness of the surface oxide on an AlCu2.2 %at alloy sample. ToF-SIMS analyses show that the oxide layer is thinner on the intermetallic particles (IMPs) as compared to the Al matrix. Combined with XPS, analyses reveal that IMPs are covered by aluminium and copper(I) oxide whereas the Al matrix is covered by

An AISI 430 stainless steel was coated by Mn-Co and Mn-Co-Cu oxides, then tested in O2-5%H2O at 800 °C. The coated samples had reduced rates of oxidation and Cr loss due to Cr-species volatilisation with the higher rates for the Mn-Co-Cu oxide coated steel due to more Cr diffusion to the coating layer. The measured rates of Cr loss were in the order of 10–11 g cm–2 s–1. The graphical representation

In this study, an optimized duplex coating, consisting of a thick Cr3C2-NiCr interlayer and a top CrN film, were designed and deposited by HVOF and PVD. And then hot corrosion behaviors were systematically investigated, and corresponding corrosion mechanisms are discussed in detailed. Results showed that the thickness of the oxide scale of duplex coating is approximately one-tenth that of the Cr3C2-NiCr

The corrosion inhibition of a combination of Na2HPO4 (DSP) and benzotriazole (BTA) for rebar in carbonated concrete pore solutions was investigated. Electrochemical methods were adopted to assess the corrosion behaviour of rebar thermodynamically and kinetically. Also, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to detect the composition of oxide films formed

The corrosion behavior of additively manufactured (AM) Al-6061 RAM2 was compared with conventional extruded Al-6061 T6 within ten days of exposure in 0.5 M NaCl solution using electrochemical measurement and microscopic observations. At the beginning of exposure, the AM samples revealed superior corrosion performance compared to extruded counterparts. However, by increasing the time of exposure, the

In this study, we performed three surface modifications for AISI H13 steel to study their protective effects in 1023 K molten aluminum. Results showed that air oxidation can produce a thin film of Fe2O3 and little FeO, and the liquid-nitriding formed a surface of iron nitrides and oxides (Fe2O3 + Fe3O4). While liquid-nitriding with post-oxidation can form a surface of Fe3O4 and little Fe2O3 by oxidizing

Press-hardened steels are commonly protected with hot-dip Al-Si coating. Due to the electrochemical complexity of this system, either before or after hot-stamping process, SKPFM was used to investigate the influence of the thermo-mechanical process on the electrochemical behaviour of the galvanic coupling. The hot-stamping process changed significantly the anodic/cathodic coupling of the coating/steel

This study investigated the effect of milling temperature on long-term high-temperature (800 °C) oxidation property of Fe-14Cr-3W-0.4Ti-0.3Y2O3 (wt.%) oxide dispersion-strengthened steel (milling temperatures were set to 25 °C (K1) and −150 °C (K4)). Atom-probe tomography results showed several nm-scale naturally formed surface oxide films containing yttrium before oxidation. Weight gains after 6000 h

The cyclic hot corrosion behaviors of TiAl based intermetallics were studied in two different molten salts consisting of % wt. Na2SO4-25NaCl and Na2SO4-25K2SO4 at 800 and 900 °C for 180 h, respectively. The aim of the study is to elucidate the effect of alloying elements on hot corrosion phenomena in the corrosive molten salt mixture. Corrosion kinetics revealed the Mo-added samples exhibit poor corrosion