The oxidation behaviour of four NiCoCrAlx medium-entropy alloys (x = 0, 0.1, 0.3, or 0.5 mol.) was investigated in dry air at 600–900 °C. The oxidation kinetics of all the alloys followed the parabolic rate law at T> 700 oC, and the oxidation rates increased with an increase in temperature and a decrease in Al content. Discontinuous oxide granules were formed on all the alloys at 600 °C, while complex

A test rig consisting of a quartz tube placed in a horizontal furnace made of five independently regulated heating zones allowed the evaluation of the metal dusting attack of a FeNiCr alloy. Fifteen samples were exposed in a temperature gradient from 504 to 704°C, 1.1 bar, to a highly carburizing atmosphere for 1500 h. Below 561°C the high density of pits led to uniform corrosion whereas localized

In high power electronics packaging, sintered silver nanoparticle joints suffer from thermal-humidity- electrical-chemical joint driven corrosion in extreme environments. In this paper, we conducted aging tests on sintered silver nanoparticles under high-temperature, high-humidity, and high-sulphur conditions. The results show that: (1) the sample under the dry high-sulphur conditions at a high temperature

Liquid-phase transmission electron microscopy (LP-TEM) has provided corrosion scientists with a unique opportunity to directly correlate nanoscopic morphological and compositional evolutions to the corresponding electrochemical response of corroding thin TEM specimens. Electrochemical liquid cell designs are key components of a LP-TEM study towards an implementation which is representative for realistic

This paper aims to explore the different oxidation behaviors of TiAlN coatings on two various substrates under thermal cycling at 750 oC. Thin oxide scale layer formed and Ti2N phase generated in TiAlN-TC4 system. IDZ composed of nitride phase appeared at TiAlN/TC4 interface after thermal cycling. By contrast, for TiAlN on stainless steel, thick oxide scale layer formed on the surface. There were no

Corrosion testing of anodized aerospace alloys is often performed by immersion and salt spray tests, according to specific international standards. The two tests differ not only in the physical exposure conditions but also in the standard testing temperature. In this work, the individual effects of temperature and exposure type on the protective performance of different anodic oxides are considered

The liquid metal embrittlement sensitivity of a low nickel 316 L austenitic steel has been studied with eutectic gallium indium alloy. The embrittlement case is firmly established with this steel and studied by X-Ray fractography and EBSD. Brittle to ductile recoveries were observed via a dedicated parametric study (varying cross-head speed and temperature). The return to ductility with temperature

Alloying trace Sn in 430LX ferrite stainless steel (FSS) can effectively inhibit the active dissolution kinetics in H2SO4 solution, which is proved by potentiodynamic and potentiostatic polarization. To clarify the mechanism of Sn and unravel the complicated polarization curves, solution simulation experiments for 0 Sn specimen were designed and Sn2+ dynamic addition tests were conducted. Results indicate

In service, automotive exhaust manifolds are submitted to rapid thermal cycling up to 700-750°C. To simulate an increase in exhaust gas temperature, a high-silicon cast iron was tested for rapid thermal cycling up to 800°C. In addition to the well-known duplex oxide scale, rapid cyclic oxidation promotes the formation of a columnar zone at the substrate/oxide interface that has never been reported

The Zr-Ti-Si-C solid solution coatings were fabricated by solid solution and in-situ reaction methods, and effects of TiC on the microstructure and phase evolution, and ablation behavior of Zr-Ti-Si-C solid solution coatings were investigated. Results show that TiC was reacted with zirconium or silicon compounds to generate even-distributed ternary ZrxTi1-xC and quaternary (TixZr1-x)3SiC2 solid solution

This study fabricated alloy films with excellent corrosion resistance by depositing an Mg film on Al-Si coated steel sheets and applying heat treatment. The fabricated Al-Mg-Si alloy film formed a corrosion product film composed of two layers, showing an excellent barrier effect against corrosion factors. The Mg in the film fabricated by heat treatment for 5 min was widely distributed in a dissolved

In situ observations of the filiform corrosion process of die-cast AZ91D magnesium alloy were carried out in 0.1 and 0.01 M NaCl solutions (pH 8.0) through a microscale polarization technique. The changes in morphology were observed in real-time using an optical microscope. Filiform corrosion proceeded in lamellar α + β structures adjacent to β phases and sometimes in the α phase grains. The β phases

The surface microstructural evolution, mechanical properties and ablation behaviors of nitrogen-doped C/C-ZrC-SiC composites by hot isostatic pressing(HIP) have been studied via multiple-characterizations. Results show that the post-treatment of nitridation has significant effects on mechanical strength with grain refinement by virtue of in-situ SEM observations. After nitridation, the dense nano-grained

To understand the oxidation mechanisms of (TiC+TiB+(TiZr)5Si3)/TA15 composites and elucidate their superior oxidation resistance, a systematically microstructural characterization of the oxide scale was investigated. The results showed that the oxide scale was consisted of the outer R-TiO2+Al2O3 mixed layer, inner gradient R-TiO2 layer, dispersive amorphous/nanocrystalline SiO2 and interfacial Ti2AlN+Ti2N

TiN coatings suffer severe hot corrosion under the synergistic effect of NaCl and mid-temperature oxidation. Multilayer microstructure is expected to improve the corrosion resistance of the TiN coatings. In this work, NaCl-induced hot corrosion behavior and mechanism of TiN single-layer coating and TiN/Ti multilayer coating at 500 ºC were studied. The TiN coating was seriously corroded along the grain

The microstructure of AZ31 magnesium alloy was modified by Ca addition. AZ31-Ca alloys with refined microstructure exhibited significantly enhanced corrosion resistance in artificial seawater. AZ31–0.5Ca showed the lowest corrosion rate of 0.716 ± 0.186 mm y−1, which was about 7.4 times lower than that of AZ31 alloy (5.326 ± 0.652 mm y−1). The dominant role in the reduced corrosion rates of AZ31-Ca

In this study, the oxidation behavior and mechanism of SiBCN monoliths were compared with SiC and SiC-BN monoliths. At 1100~1300 °C, the oxide layers of SiC and SiBCN monoliths were relatively smooth and dense, while that of SiC-BN monoliths were destroyed by many bubbles. Further oxidized at 1500 °C, some cracks and bubbles appeared on the surfaces and interfaces of SiC-BN monoliths. The oxidation

The effect of Ta on the oxidation resistance of the alloys Tax-(Mo-Cr-Ti-Al)1-x (x = 0; 5; 10; 15; 20 at.%) in air at 1200°C was examined. The oxidation behavior improves continuously with the increasing Ta concentration. Alloys with Ta concentrations Ta ≤ 10 at.% exhibit poor oxidation. Severe evaporation of MoO3 occurred which was quantitatively estimated. The evaporation of MoO3 is drastically reduced

The application of coating to cladding materials can potentially improve the accident-tolerant fuel cladding for light water reactors. In this study, oxidation behavior of five CrAl-based coatings containing different amounts of Al deposited onto Zr-4 alloy exposed to high-temperature air is investigated. The results demonstrate that pure Cr coating exhibits excellent oxidation resistance due to the

The effect of Au-ions irradiation with different damage doses from 10 to 90 dpa on mechanical properties and LBE corrosion behavior of AlCrFeMoTi HEA coating was investigated. The fracture toughness and the interface bonding strength had been improved after irradiation. The Au-ions irradiation decelerated LBE corrosion rate of coating at low damage dose, which could be attributed to the formation of

In this work, a water chemistry model was developed by combining the activity coefficient-fugacity coefficient type solubility model and species equilibrium model to determine the mutual solubilities of CO2 and H2O, and the corresponding species concentrations in the CO2-mixed salts-H2O system (mainly contains Na+, Ca2+, Mg2+, K+, Cl-, and SO42-) with the temperature range of 15–250 °C, the pressure

Ni/NiFe2 dual layer coating is fabricated to improve the performance of SUS 430 steel as solid oxide fuel cells (SOFCs) interconnects by a combined approach. Ni layer is deposited by electroplating or magnetron sputtering, and subsequently the NiFe2 layer is sputtered on it. The coated steels are evaluated at 800 °C in air corresponding to SOFC cathode environment. It is found that the coating with

Inhibition performance of 2-hydroxybenzimidazole (2-OH-BI), 2-aminobenzimidazole (2-NH2-BI) and 2-mercaptobenzimidazole (2-SH-BI) on under-deposit corrosion (UDC) of carbon steel beneath CaCO3 and SiO2 deposits in CO2-saturated solutions were investigated by electrochemical measurements and surface analyses. The results show that the inhibition efficiency follows the order of 2-SH-BI > 2-NH2-BI > 2-OH-BI

Cr/CrxN coatings were deposited on Zr-4 substrates by multi-arc ion plating for accident-tolerant fuel coatings. The effect of the Ar/N2 flow ratio on the microstructure, mechanical properties, and high-temperature steam oxidation behavior of the coatings was investigated systematically. All coatings significantly increased the oxidation resistance of Zr-4 by forming a Cr2O3 oxide layer, and the performance

In this study, we describe a smart coating that responds to either an increase or a decrease in pH to assist inhibitor effectiveness. Dual-pH sensitive microspheres containing a corrosion inhibitor were fabricated using a simple, template-free, one-step process. A polyelectrolyte coacervate consisting of polyacrylic acid and polyethylenimine was the shell material of microspheres that enclosed Ce(NO3)3

A self-passivating W-Si-Y alloy was prepared by spark plasma sintering, while the microstructure evolution and oxidation mechanism at 1000 °C were analyzed. The alloy exhibits excellent oxidation resistance due to the introduction of Y. At high temperatures, Y enriches on the surface of the oxide scale, and a melt mainly containing W, Y and O is formed. The melt can close the pores on the surface of

Besides their noteworthy tribological and corrosion protection properties, Plasma Electrolytic Oxidation (PEO) coatings feature a porous microstructure that is able to host corrosion inhibitors. This study reveals that although 2,5pyridindicarboxylate (2,5PDC) shows a remarkable corrosion inhibition effect for bare AZ21 Mg alloy, it can extensively deteriorate a PEO coating on the same Mg substrate

The corrosion behavior of weathering steel in the environments with different NaCl concentrations was systematically investigated. The results indicated a decrease of corrosion resistance of steel as NaCl concentration increased. While, the weight gain rate in high concentration was lower than that in lower conditions, which was attributed to the inhibition on the diffusion of O2 caused by the residual

The effects of atmosphere (oxygen and steam) and reactive element addition (Zr and Y) on high-temperature oxidation behavior of Al0.5CrFeNiMn and Al0.5CrFeNiCo high-entropy alloys at 1000 °C and 1200 °C were studied. The Al0.5CrFeNiMn alloy displayed different oxidation mechanisms in oxygen and steam owing to differing oxygen partial pressures and preferential oxidation of Mn. A protective alumina

Improving the long time ablation resistance of thermal protective coating is the key index to promote the development of hypervelocity aerocrafts. In this work, the ablation behaviors of ZrB2-MoSi2 and ZrB2-MoSi2-WB composite coatings fabricated by vacuum plasma spray (VPS) were evaluated by plasma flame. The microstructure evolution induced by prolonged ablation was focused on and discussed in detail

HfC coatings were deposited on the surface of carbon/carbon (C/C) composites and CVD-SiC coating by low-pressure chemical vapor deposition (CVD), respectively. The effects of two substrates on the microstructure, phase composition and preferred orientation of HfC coatings were investigated in detail. Results showed that HfC coatings deposited on two substrates inherit their own substrate surface characteristics

The effect of Lu2O3 on the oxidation behavior of SiC-ZrB2 composite coating at 1500 ℃ in static air was investigated by oxidation test and first-principles simulations. The Lu2O3-SiC-ZrB2 composite coating protected C/C composites from oxidation at 1500 ℃ for 836 h with a mass gain of only 0.62 mg/cm2. The introduction of Lu2O3 was beneficial for improving the densification of Lu2O3-SiC-ZrB2 composite

In this study, the stable dissolved valence state of iron fluorides in molten LiF - NaF - KF (FLiNaK) salt and their effect on GH3535 alloy were systematically investigated. Results of in situ ultraviolet–visible (UV–Vis) absorption spectroscopy and electrochemical analysis indicated that Fe (II) in molten FLiNaK salt is unstable and gets converted to more stable Fe (III) through the disproportionation

The microstructures of Febalance-18Cr-12Ni-1.5Mn-0.07C (in wt%) alloys containing 0.2–1.76 wt% B were controlled through hot rolling of 60% and 96%. It was found that refining the microstructure through additional hot rolling helped to form a stable passive film and accelerate passivation. Passive film formed on the 96% hot-rolled BSS exhibited higher electrical resistant than that of the 60% hot-rolled

In this study, Mo-60Si-5B coating doped with 0.5 at% La was deposited on Nb-Si based alloy by spark plasma sintering and the oxidation resistance of the coating at 1300 ℃ was investigated. The results show that the mass gains of 0.5La-Mo-60Si-5B and Mo-60Si-5B coatings are 0.85 mg/cm−2 and 1.02 mg/cm−2 after oxidation at 1300 ℃ for 100 h, respectively. Good oxidation resistance of the coating is attributed

HfC coatings with different microstructure were successfully fabricated by chemical vapor deposition. The mechanical properties and ablation resistance of HfC coatings were evaluated, and the coefficient of thermal expansion (CTE) and ablation behavior of the as-prepared coatings were investigated in detail. Results showed that HfC coating with the dense coarse columnar structure exhibits good mechanical

Accelerated cut-edge corrosion performance of commercialized full waterborne coating systems containing enviro-friendly corrosion inhibitors was studied on 55 wt% Al, 44 wt% Zn and 1 wt% Si galvanized steel in 5 wt% NaCl solution at ambient temperature via the Scanning Vibrating Electrode Technique (SVET). At the same volume content (7–11 wt%), benzotriazole pigments had a better overall cut-edge corrosion

Corrosion behavior of pure titanium in H2SO4, HCl and HNO3 with different concentrations of F- was studied with electrochemical testing and morphology observation. The threshold F- concentration triggering severe corrosion is between 0.0005 and 0.001 M in the three acids. The F- promotes anodic dissolution and inhibits oxygen reduction, resulting in the decrease of cathodic current density. The corrosion

To support the application for piston of advanced internal combustion engine and pantograph slide plate of high-speed rail, cyclic ablation with different loading spectrums in alternate plasma combustion and compressed air flow were performed by adjusting single impacting time to understand the characteristics of C/C-SiC-ZrB2-ZrC composites in high frequent pulsing fluid at ultra-high temperature.

Using no catalyst, hafnium carbide nanowires (HfCnws) layer was in-situ synthesized and its controllable growth was realized on carbon/carbon (C/C) composites. Microstructural evolution from CNTs to HfCnws revealed that the growth of HfCnws was based on vapor-solid (VS) mechanism and root growth was the common growth type. Increased relative content of carbon source reduced the aspect ratio but promoted

The transient oxidation behavior of magnetron-sputtered chromium-coated Zircaloy-4 was studied in steam up to 1600 °C, and the microstructural evolution of the coating-substrate system after oxidation was investigated. Coating failure and corresponding rapid oxidation of coating and substrate occurred at 1300–1400 °C. It was mainly caused by the thickness decrease of the outer dense Cr2O3 scale, the

Building a gradient structure can achieve overall improvement of multiple properties of metal materials. However, the investigation on hydrogen embrittlement (HE) behavior of gradient structure alloys has not been reported so far. This study investigated HE of pure iron with gradient microstructure induced by pre-torsion. The results reveal that with an increase in pre-torsion angle, the resistance

To enhance the high-temperature oxidation resistance of Ti6Al4V alloy, an anti-oxidation coating is fabricated on Ti6Al4V by simple surface aluminization. The interdiffusion of Al/Ti leads to the TiAl3 formation. With the increasing diffusion temperature or holding time, Al is depleted, and the generated TiAl3 reacts with Ti subsequently, forming the Ti-Al IMC layers. A smooth, dense, and uniform coating

Hydrogen permeation tests were conducted in 1.2 MPa H2 on welding thermal simulated specimens to determine the hydrogen permeation parameters in each subzone of the girth welded joints. Optical microscope, electron back-scattered diffraction, and X-ray diffraction were applied to analyze the corresponding microstructure changes. The results show that the hydrogen diffusion coefficient D is mainly determined