The tellurium (Te) corrosion behaviors of the hot-rolled GH3535 alloy have been investigated systematically in this study as compared with the standard solid-solution treated one. In the hot-rolled alloy, the higher proportion of Cr3Te4 and MnTe can be observed in the corrosion scales. Beneath the scales, Te was found to enrich in the primary M6C carbides rather than at the grain boundaries. The blocking

Microbially influenced corrosion (MIC), is acknowledged to be the direct cause of catastrophic corrosion failures, with associated damage costs ranging to many billions of US$ annually. In spite of extensive research and numerous publications, fundamental questions relating to MIC remain unanswered. The following review provides an overview of current MIC research and stresses the lack of information

The corrosion behaviour and passive films formed on Ni-based single crystal superalloys with different orientations were investigated through the electrochemical testing and microstructural analysis. The results show that the corrosion rates of the different planes increases in the order of (001) < (111) < (011), which can be attributed to the higher equivalent atomic packing density and more compact

Thermal protection systems with long time anti-ablation property for applications in ultrahigh temperature environments have been a choke point for the development of hypersonic vehicles. In the present work, new ZrC-SiC-TiC ternary composite coatings were designed and fabricated by vacuum plasma spray. The ablation behaviors of the ternary coatings were evaluated by a plasma flame with temperatures

This work presents the first corrosion analysis of 4-methyl-2-phenylimidazole (MePhI) corrosion inhibitor for brass immersed in 3 wt.% NaCl solution, wherein MePhI was shown to be highly effective. The structure of the surface layer, the formation of an organo-metallic complex, the spatial distribution of MePhI, and the thermal stability of the MePhI surface layer were described in detail using time-of-flight

The presented study was devoted to the characterization of a scale formed on the ATI 718Plus® superalloy. Novel complementary techniques were applied to precisely describe the structure, chemistry, morphology of the scale as well as the spatial distribution of phases formed during oxidation. The study revealed a discontinuous interlayer of the δ-Ni3Nb phase that had developed underneath the protective

Alkaline etching as an anodization pretreatment process is critical to structure and anticorrosion performance of the anodic film. The effects of modification by alkaline etching on AA6061 surface microstructure and corresponding film growth behaviors have been investigated in this work. The in-situ characteristics of grain boundaries, intermetallic particles and film structure were investigated. It

The corrosion rate of Cr in molten FLiBe–CrF3 and FLiNaK–CrF3 was studied by electrochemical impedance spectroscopy and static immersion analysis. Corrosion in FLiNaK–CrF3 was greater than that in FLiBe–CrF3. The Cr corrosion kinetics were studied by high-temperature in situ ultraviolet-visible spectroscopy at 600 °C. In molten FLiBe–CrF3, the corrosion product was Cr(II), whereas in FLiNaK–CrF3, Cr(II)

The formation and evolution of corrosion product scales on 13Cr stainless steel at 200 °C and various CO2 partial pressures were investigated. Scanning electron microscope was used to show the physical nature of the scales formed at 0.27 MPa CO2. The thin non-uniform layer was identified as FeCr2O4 by Raman Spectroscopy with a thick Cr(OH)3 layer being determined at 2.85 MPa CO2. These results provide

In this study, the different corrosion behaviors between α and β phases of Ti6Al4V in solutions with different NaF concentrations are investigated. When the NaF concentration changes from 0.15 to 0.20 M, α phases are more likely to suffer from corrosion than β phases. However, the formation of a repassive film makes α phases exhibit superior corrosion resistance than β phases as the NaF concentration

Degradation of plasma sprayed GdMA and YSZ coatings attacked by CMAS was comparatively investigated at 1350 °C for 1 h, 12 h and 48 h in air. Results show that GdMA coating exhibited much better CMAS attack resistance than the YSZ coating. Presences of Gd, Mg and Al elements facilitated formations of the Ca2Gd8(SiO4)6O2 apatite, MgAl2O4 spinel and CaAl2Si2O8 anorthite crystals effectively arresting

The ASTM G67 Nitric Acid Mass Loss Test (NAMLT) is not a universally accurate proxy for intergranular stress corrosion cracking (IG-SCC) susceptibility in Al-Mg alloys. This study aims to understand this discrepancy via an electron backscatter diffraction (EBSD) and ammonium persulfate etching/overlay analysis to characterize the linear grain boundary β coverage (LGBBC). Testing at three NAMLT levels

The role of subgrain stripe on the exfoliation corrosion behavior in the Al-4.6 wt%Mg-3.1 wt%Zn alloy is revealed. The slight difference in the Volta potential distribution between the subgrain stripes and normal grains indicates that the selective corrosion in the subgrain stripes is not relevant to the electrochemical factor. Furthermore, the difference in the microstress state between two sides

Short-term isothermal oxidation of TiAl 48-2-2 alloy produced by Electron Beam (EBM) was investigated at 750, 800, 850 and 900 °C with special focus on the oxidation kinetics and metal-scale interface evolution. It was shown that at the lowest oxidizing temperature a passivating and thin mixture of alumina and titania is formed with subsurface Z-phase formation. At higher temperatures a porous and

The corrosion behaviour and Cr retention ability of SS309, aluminised SS309, and AluChrom 318 have been investigated at 850 °C in air with 3% H2O. The SS309 samples failed the specifications for application as cathode air preheater (CAPH) material due to a high Cr evaporation rate and massive scale spallation. The surface aluminisation dramatically decreased the Cr evaporation rate of SS309, but not

Dynamic processes at the Ni│H3PO4+KSCN interface during the anodic dissolution were observed in situ without and with the magnetic field (MF) by the digital holography. Potentiostatic current oscillations appeared in the pre-passive region, because the newly-formed NiOOH passive layer could be dissolved by SCN- ions. MF enhanced the mass-transport step and accelerated the dissolution of the surface

Surface, stagnant grain boundary (GB), and crack tip oxidation of Alloy 600 were studied. The mirror-finished surface oxide has a duplex structure and the formation mechanisms of each layer are discussed. A more compact oxide film is observed on the cold-worked surface, while the nano-GBs are preferentially oxidized. The crack tip oxidation rate is around four orders of magnitude faster than that of

The effect of direct current (DC) stray current on passivation behavior of low-carbon (LC) reinforcing steel and a 10%Cr reinforcing steel in saturated Ca(OH)2 solution was investigated by means of EIS, AFM and XPS measurements. In addition, cyclic potentiodynamic polarization curves were employed to evaluate the influence of stray current on chloride-induced pitting corrosion behavior of steels. The

The effects of heat treatment on the microstructure and high-temperature oxidation of selective laser melted TiC/IN625 nanocomposites were studied. Refined cellular grains, many dislocation structures and high proportion of sub-grain boundaries appeared in the as-built TiC/IN625 nanocomposites. After heat treatment (HT), the recrystallized grains and annealed twins did not appear in the TiC/IN625 nanocomposites

A SiC/ZrB2-SiC/SiC triple-layer coating was fabricated successively by chemical vapor deposition (CVD), slurry brushing-sintering and CVD for C/SiC composites. To enhance the cyclic ablation resistance, a pre-oxidation treatment on the inner SiC layer was performed. The bonding strength of the coating with pre-oxidation at 1600 °C is significantly improved to 32 MPa, 77.8% greater than that of the

The effect of sulphur compounds and temperature on the microbiologically influenced corrosion of carbon steel has been assessed using multispecies biofilms. Biofilm composition, community structure and activity level shifted in response to environmental conditions, which resulted in substantial differences in pitting susceptibility of carbon steel. Microorganisms enhanced pitting when sulphur compounds

In this work, the oxidation behaviour of Cu-added 18 %Cr-8%Ni alloy was investigated. A duplex scale with outer Fe3O4 and inner FeCr2O4 layers was formed on the alloy surface. Due to its low oxygen affinity, Cu was ejected and segregated around the Fe3O4/FeCr2O4 interface and the scale/matrix interface during oxidation. Moreover, the supersaturation of Cu at the subsurface facilitated the extensive

Silicone-based composite coatings modified by ZrO2 nanoparticles were applied on the 1Cr11Ni2W2MoV steel. Their oxidation and corrosion performances were evaluated in air and an environment containing solid NaCl and water vapor at 600 °C, respectively. The coating with 20 wt.% ZrO2 exhibited better oxidation resistance than those with 10 and 30 wt.% ZrO2, while the coating with 20 or 30 wt.% ZrO2 exhibited

The influence of sulphide on the electrochemistry of carbon steel in neutral to slightly alkaline sulphide solutions was investigated using electrochemical and surface analytical techniques. Small concentrations of sulphide were found to promote anodic dissolution as FeII carbonate complexes and to destabilize FeIII oxides leading to the loss of passivity, especially at pH ≤ 9. The dominant phase formed

We discuss kinetic and thermodynamic aspects of carbon steel corrosion in CO2-containing NaCl fluids up to 240 °C. Crystalline nm-thick Fe-oxide films only form at 160 °C and 240 °C providing instantaneous and moderate corrosion protection. The absence of Fe-oxide at 80 °C results in high initial corrosion rates until a moderately protective, but thick and porous, FeCO3 film forms. From the metal/film

We report dealloying of Ti60Ta40 in molten copper, eutectic Cu28Ag72 alloy and Cu20Ag40Bi40 alloy for the fabrication of ultrafine Ta ligament structures across a 1-mm thick section. When dealloyed in molten Cu and Cu20Ag40Bi40, the melt temperature dictated the length scale of Ta ligaments, which decreased exponentially with decreasing temperature. Conversely, dealloying in molten eutectic Cu28Ag72

The effect of Cr content in steel on its passivation behavior in a CO2 aqueous environment containing silty sand was investigated. The results indicated that the stability of passive film was improved with increasing Cr content. High Fe3C content accelerated the rapid formation of a passive film as well as precipitates and dislocations. Increasing Cr content enhanced the contents of Cr2O3 and Cr(OH)3

Time–evolution study of 2-(2-pyridyl) benzimidazole (2PB) as CO2 corrosion inhibitor for API X60 steel under hydrodynamic conditions in a synthetic brine solution has been undertaken. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques were employed for this study. The results indicate that 2.56 mM of 2PB could provide up to 88.3 % inhibition efficiency after

Si-Mo alloy was infiltrated into porous graphite to develop a short-term low-ablative SiMo/graphite composite material. 19.4 vol.% residual Si was retained in the composites and significantly improved the short-term (less than 60 s) ablation resistance without sacrificing long-term (∼180 s) ablation resistance. The excellent short-term low-ablative performance is ascribed to the melt and evaporation

The effect of flow velocity, pH and lithium concentration on corrosion product deposition in accelerated flow regions was investigated in simulated nuclear reactor primary water using discs containing micro-orifices. The results also showed that a well adhered crystalline deposit formed between 2 and 2.5 ppm lithium, where the zeta potential of stainless-steel specimens is negative and the electrokinetic

This paper reports the results of corrosion study for carbon steel, austenitic stainless steel, as well as titanium and nickel-based alloys which were tested in a simulated superheated geothermal environment (SSGE) in flow-through reactors to investigate the corrosion behaviour to aid in the future material selection for high temperature deep geothermal application. The testing fluid was superheated

Yttria-stabilized zirconia thermal barrier coatings (YSZ TBCs) are prone to degradation by atmospheric contaminants such as volcanic ash, posing a serious threat to their durability. Here we demonstrate that hexagonal boron nitride (h-BN) additives to YSZ coatings (h-BN YSZ), exhibit resistance against volcanic ash interaction at 1250 °C. In preliminary tests performed under vacuum, h-BN YSZ coatings

The corrosion resistance of 17-4PH stainless steel obtained by Selective Laser Melting was investigated. It was found that the as-built SLM-ed steel was entirely ferritic, not martensitic as expected. Re-austenitized SLM-ed steel recovered the martensitic microstructure. The two SLM-ed steels (as-built and re-austenitized) had the same general corrosion resistance which was correlated with their similar

The corrosion behaviours of GH3535 alloy in molten FLiNaK eutectic salt (LiF-NaF-KF: 46.5-11.5-42.0 mol.%) were investigated in the presence and absence of graphite particles by using a static immersion corrosion technique. Results indicated that graphite particles barely affected the corrosion rate of chromium in the subsurface and increased the corrosion loss of GH3535 alloy in molten salt. These

A low-diffusion (Ni,Pt)Al coating with Re-base diffusion barrier was prepared on a second-generation single-crystal superalloy via electroplating and gaseous aluminizing, in which the electroplating consisted of depositing Ni-Re and Pt, sequentially. Compared with normal (Ni,Pt)Al, cyclic and isothermal oxidation performances of the coating with Re-base DB were evaluated at 1100 °C in static air. It

The superior oxidation resistance of oxide dispersion-strengthened FeCrAl-base alloys is due to the formation of a slowly growing alumina scale on the surface. In this study, the growth mechanism of oxide scale formation on yttria-dispersion FeCrAl alloy with and without Pt doping was studied during oxidation at 1200℃ in air. The morphologies of the alumina scales and compositions of the oxides on

Hot corrosion behaviors of TiAl coatings with different Nb and Si additions in a Na2SO4 + NaCl salt mixture at 800 °C were investigated. Corrosion kinetics was evaluated based on mass change measurements. The corrosion products and morphologies of the corrosion scales were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adhesion strength of the corrosion scales was evaluated

An electrically conductive coating was prepared on micro-arc oxidized (MAO) Mg alloy AZ31 via antimony tin oxide (ATO) particles doping in methyltrimethoxysilane (MTMS) coating. A sandwich structure was observed as the ATO particles agglomerated at the top and bottom layers in the MTMS coating via field-emission scanning electron microscopy (FE-SEM). Electrochemical and hydrogen evolution tests revealed

In this work, beneficial effects of dissolved oxygen (DO) on the crack initiation and propagation in borated and lithiated high temperature water were observed, which finally increased the low-cycle fatigue (LCF) life of the 316 L N in the water. The 100 ppb DO added in the water also reduced the total amount of absorbed hydrogen. Meanwhile, the oxide film formed was more protective compared with the

Bioenergetic analysis implies that microorganisms can harvest the released energy from metal corrosion for survival via extracellular electron transfer (EET) under carbon-starvation conditions. In this work, we combined carbon starvation with CTC/DAPI counterstaining and developed a novel method for detecting EET from metal substrate to the cells. A wild-type of nitrate-reducing bacterium (NRB) Bacillus

Hydrogen evolution and dissolution of Aluminium (Al) have been investigated at different anodic potentials in de-oxygenated 3.5% NaCl electrolyte to afford new insights into its negative difference effect (NDE). Innovatory to previous reports, the instantaneous concentration of dissolved Al3+ ions was detected using a novel in-situ electrochemical ICP-OES technique and a dissolution stoichiometry of

The ignition and onset melting temperatures, surface morphologies before and after ignition, as well as combustion products of Mg-xAl (x = 0, 3, 6 and 8 wt.%) alloys were investigated. The results demonstrate that ignition process of Mg-xAl alloys in this research, take to be pyrolysis/gasification and piloted ignition of pyrolysis volatiles. Besides, Mg-0Al and Mg-3Al alloys gasification mainly occur