Oxidation of Metals最新文献

Marine energy resources development and deep-sea exploration fields put forward higher demand for high-temperature and corrosion-resistant materials in service. In this work, the high-temperature oxidation behavior (800 °C) of a corrosion-resistant Cu-Ni-Fe-Mn alloy was systematically investigated by combining the CALPHAD technique with experiments. Both thermodynamic calculations and experimental characterizations revealed that Fe and Mn solute segregation in the as-cast alloy resulted in non-uniform oxidation, leading to accelerated oxidation and premature oxide layer cracking. Homogenization effectively reduced the parabolic rate constant (kₚ) from 3.73 × 10⁻⁹ to 3.38 × 10⁻⁹ mg²·cm⁻⁴·s⁻¹, indicating improved oxidation resistance. By integrating CALPHAD-based segregation modeling and local Pilling-Bedworth ratio (PBR) calculations, a semi-quantitative link was established between solute segregation, oxide composition, and cracking tendency. The calculated PBR values (2.04 for as-cast vs. 1.93 for homogenized) reflect the magnitude of oxidation-induced volume expansion stress and correlate with the observed differences in oxide layer spallation. Homogenization treatment effectively reduced Fe/Mn segregation, lowered the PBR, and improved oxide uniformity and adherence. Furthermore, the oxide layer was composed of an outer CuO layer and an inner Halite-type ((Ni, Fe, Mn) O) phase, whose stability enhanced oxidation resistance.

This work investigates the influence of 2.02 wt.% V addition on the oxidation behaviour of a high-Mn austenitic heat-resistant steel at 1173 K in air to understand the effect mechanisms of V on the oxidation damage. The oxidation products and the structures of the oxide scale are systematically examined. The results of oxidation tests indicate that the base steel exhibits parabolic oxidation behaviour, whereas the V-containing steel follows linear oxidation kinetics. The mass gain after oxidised for 100 h of the base steel is only 51% of that of the V-containing steel. This demonstrates that the addition of V significantly degrades the oxidation resistance of high-Mn austenitic heat-resistant steel at 1173 K. Furthermore, the analysis of the oxide scales and subsurface microstructural evolution of the two steels reveals that the oxidation of the base steel is controlled by the outward diffusion of alloying elements, while that of the V-containing steel is governed by the inward penetration of oxygen. This also explains the catastrophic oxidation observed in the V-containing steel. Finally, the oxidation damage in the base steel is primarily attributed to the combined effects of Cr depletion-induced failure of the protective oxide scale and internal oxidation. In contrast, the oxidation damage in the V-containing steel results from the synergistic action of two factors: (1) the formation of low-melting-point oxides such as V₂O₅ and CrVO₄, which act as oxygen carriers and accelerate oxygen ingress into the matrix, and (2) reactions between V₂O₅ and other oxides that prevent the formation of a continuous protective oxide scale.

Corrosion-induced material degradation poses significant challenges in high-stakes industries such as aerospace, oil and gas, and power generation. This review provides a comprehensive analysis of four primary corrosion failure mechanisms - stress corrosion cracking (SCC), hydrogen embrittlement (HE), pitting corrosion, and uniform corrosion - with focus on their initiation, progression, and impact on advanced materials under extreme environmental conditions. Emphasis was given to the critical role of environmental factors such as temperature, humidity, and aggressive chemicals in accelerating corrosion processes. The review also highlights the application of advanced microscopic techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), ultrasonic imaging, and in situ Raman spectroscopy with DFT calculations, which enable detailed insights into microstructural changes and surface degradation associated with corrosion. Furthermore, emerging corrosion-resistant materials, such as high-entropy alloys and self-healing coatings, are discussed alongside innovative technologies such as machine learning, digital twins, and real-time corrosion monitoring which hold promises for enhancing material durability and optimizing maintenance strategies. Despite notable advancements, challenges remain in addressing the combined effects of multiple environmental factors and the long-term behavior of novel materials. Future research must focus on developing integrated, multiscale predictive models, improving real-time monitoring systems, and advancing corrosion-resistant technologies to mitigate material degradation in critical industrial applications.

This paper studies the influence of laser shock peening (LSP) on the high-temperature oxidation behavior of NiPtAl-Hf coatings and evaluates their performance under thermal cycling conditions. The surface morphology and microstructure of the coatings were characterized and analyzed. High-temperature service performance was evaluated by examining the phase transition of θ-Al₂O₃ and α-Al₂O₃ and the evolution of the thermally grown oxide (TGO) through transient oxidation and thermal cycling tests. Results showed that LSP significantly promotes the phase transition from θ-Al₂O₃ to α-Al₂O₃. The effect is attributed to the high-density dislocations and plastic deformation regions introduced by LSP, which provide abundant heterogeneous nucleation sites for α-Al₂O₃. Comparative cyclic oxidation experiments further showed that LSP refines the grain structure and introduces dislocation networks, enhancing aluminum diffusion for selective oxidation and mitigating thermal stress generated during thermal cycling process. Consequently, the TGO exhibits more stable growth with reduced cracking. Additionally, LSP introduces a high density of dislocations, which can act as short-circuit diffusion channels for the rapid diffusion of Al element. The accelerated Al supply promotes the rapid formation of a continuous and dense Al₂O₃ film during the initial stage of oxidation. These findings highlight the potential of LSP as an effective strategy to enhance the thermal cycling performance of NiPtAl-Hf coatings for high-temperature applications.

SiC/SiC ceramic matrix composites (CMCs) are desired for use in combustion environments to achieve higher turbine operating temperatures. However, CMCs require environmental barrier coatings (EBCs) for protection from the gas environment. EBC systems are known to primarily fail through coating delamination via growth of a thermally grown oxide (TGO) at the EBC—silicon bond coating interface when exposed to steam, which accelerates the TGO growth rate. The TGO undergoes a phase transformation during thermal cycling, which results in stresses that may encourage EBC spallation. Yb-silicate EBCs with mullite and yttrium aluminum garnet (YAG) dopant additions were deposited on SiC substrates with a Si intermediate bond coating and exposed to thermal cycling in steam at 1350 °C. The impact of Al dopant additions on the TGO growth rate and the SiO₂ phase transformation was assessed. Photo-stimulated luminescence spectroscopy (PSLS) was used to characterize the Al-containing phases and to measure stress evolution in the EBC following exposure using the stress-induced peak shift of the R-lines of mullite. Raman microscopy was used to map the stresses in the Si bond coating following exposure. It was found that the TGO phase transformation upon cooling increased compressive stress in the Si bond coating within 15 µm of the TGO.

Press hardening steel (PHS) is the most widely used material in automotive white bodies owing to its excellent formability and low springback. While replacing Ti with Al ensures the hardenability of PHS without compromising its toughness, grain boundary oxidation inevitably occurs during hot-rolled coiling. This phenomenon, driven by the oxygen affinity of alloying elements such as Si and Mn, adversely affects subsequent processing. Current research predominantly focuses on the mechanisms by which Si and Mn contribute to grain-boundary oxidation, whereas the influence of Al has seldom been explored. In this study, tube-sealed heating was employed to simulate the hot-rolled coiling process, specifically investigating the effect of Al on grain-boundary oxidation. The results demonstrate that Al inhibits grain-boundary oxidation through the following mechanisms: Al reduces the oxygen adsorption rate at the scale/matrix interface, thereby lowering the oxidation rate; and Al promotes decarburization and facilitates the enrichment of Si and Mn at the scale/matrix interface. This decarburization accelerates the dissociation of FeO, and the majority of the dissociated oxygen ions combine with the enriched Si and Mn at the interface to form oxides. Consequently, less oxygen enters the steel matrix.

To investigate the effect of recrystallization and pre-aging treatment on the oxidation resistance of alumina-forming austenitic (AFA) steels, the oxidation behavior and related mechanism of a 25Ni15Cr AFA steel under different microstructural conditions were systematically investigated at 1123 K in dry air. The results demonstrated that recrystallization treatment significantly enhanced the oxidation resistance of the AFA steel compared with that of the solid solution-treated sample, whereas subsequent pre-aging treatment failed to provide a further improvement. The recrystallized sample developed a uniform and dense oxide scale composed of fine oxide grains, primarily due to the accelerated diffusion of aluminum facilitated by grain refinement. In contrast, precipitates formed during pre-aging resulted in a negative impact on the oxidation resistance of AFA steel. The B2-NiAl phases caused uneven oxidation of aluminum, while the Laves phases hindered the short-circuit diffusion of aluminum along the grain boundaries of alloy matrix, thereby compromising the uniformity of the oxide scale. Based on the experimental findings, an oxidation model was developed to elucidate the influence of different microstructures on the oxidation mechanisms of the AFA steel.

This paper evaluates the oxidation behavior of T91 ferritic/martensitic steel exposed to flowing oxygen-saturated lead–bismuth eutectic (LBE) with a 90° impact angle at 500 °C, using multiple characterization techniques. Complex multilayered oxide scales with an alternating Fe–Cr spinel-magnetite characteristic were observed under the current condition. This contrasts sharply with the typical double-layered oxide scales observed in static LBE environment, which consist of Fe–Cr spinel and magnetite. More importantly, such multilayered oxide scales in the current condition display a much higher growth rate. After 1000 h of exposure, their thickness reached ~ 32 μm, nearly 1.5 times greater than that in static oxygen-saturated LBE. The accelerated growth is attributed to enhanced oxygen transport, promoted by the penetration of liquid LBE into the interface between the Fe–Cr spinel and the substrate due to partial exfoliation of adjacent oxides. In addition, the formation of abundant crystal defects within the surface region of the substrate induced by the impact of flowing LBE should also play a role. Finally, a possible physical model is proposed and discussed.

The corrosion of 316L steel fabricated by selective laser melting (SLM) and by forging has been studied at 800–900 °C in a H₂/H₂S/CO₂ (Gas I) and a H₂/CO₂ (Gas II) gas mixture providing the same oxygen partial pressure. Both steels behaved protectively in Gas II, while they suffered heavy sulfidation in Gas I, except for the SLM steel corroded at 900 °C, probably due to a larger concentration of grain boundaries, favoring a faster diffusion of chromium to form an external chromia scale. Moreover, the fine-grained microstructure of SLM 316L showed rather good stability after 50-h performance up to 900 °C.

NiCo-based alloys are widely recognized as superior high-temperature self-lubricating materials. Nevertheless, they are prone to failure due to severe oxidation, and the research on solving this issue remains insufficient. In the present work, simple model Ni20Cr–xCo–3Al (wt%) alloys were fabricated by using mechanical alloying (MA) and spark plasma sintering (SPS), and their isothermal and cyclic oxidation behavior at 800 °C in air for 100 h was investigated. Results show that, as the Co content increases, the alloys presented a microstructural change from coarse grain to heterogeneous structure with ultrafine grains surrounding the coarse ones. The alloy containing 30 wt% of Co successfully formed a thinner, flatter, denser and more intact external α-Al₂O₃ scale in both isothermal and cyclic oxidation, exhibiting remarkable oxidation resistance compared with the other alloys. This arises from the favorable balance between elemental diffusion and oxidation, attributed to its heterogeneous structure.