Pub Date : 2026-01-01DOI: 10.1016/j.corsci.2025.113589
Long Zhou , Xu Zhang , Ziyu Zhang , Jibo Tan , Xinqiang Wu
Corrosion fatigue (CF) behavior of stainless steel weld metal in high temperature water environment at the strain rate of 0.004 %s−1 was investigated under different strain amplitudes (0.3 %, 0.6 %, 0.8 %). A degradation in fatigue life was observed and the environmental fatigue correction factor (Fen) increased with decreasing strain amplitude. Intergranular ductility dip cracking (DDC) welding defects were found in stainless steel weld metal, promoting initiation and propagation of CF cracks. It was found that stress concentration and the obstruction of Cr oxides at the γ/δ phase boundary increased the susceptibility to phase boundary cracking under high strain amplitude. Mechanisms involving DDC cracks, strain amplitude, phase boundary and δ-ferrite on CF damage are discussed.
{"title":"Effect of strain amplitudes and ductility dip cracking on corrosion fatigue behavior of stainless steel weld metal in high-temperature pressurized water","authors":"Long Zhou , Xu Zhang , Ziyu Zhang , Jibo Tan , Xinqiang Wu","doi":"10.1016/j.corsci.2025.113589","DOIUrl":"10.1016/j.corsci.2025.113589","url":null,"abstract":"<div><div>Corrosion fatigue (CF) behavior of stainless steel weld metal in high temperature water environment at the strain rate of 0.004 %s<sup>−1</sup> was investigated under different strain amplitudes (0.3 %, 0.6 %, 0.8 %). A degradation in fatigue life was observed and the environmental fatigue correction factor (F<sub>en</sub>) increased with decreasing strain amplitude. Intergranular ductility dip cracking (DDC) welding defects were found in stainless steel weld metal, promoting initiation and propagation of CF cracks. It was found that stress concentration and the obstruction of Cr oxides at the γ/δ phase boundary increased the susceptibility to phase boundary cracking under high strain amplitude. Mechanisms involving DDC cracks, strain amplitude, phase boundary and δ-ferrite on CF damage are discussed.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"261 ","pages":"Article 113589"},"PeriodicalIF":7.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145897959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.corsci.2025.113588
A. Chyrkin , J.-P. Roth , D. Naumenko , K. Jahns
High-temperature oxidation of additively manufactured (AM) Ni-base alloy IN625 has been studied in air and Ar-4 %H2-2 %H2O for up to 1000 h at 900 and 1000 °C. AM was produced from the same conventionally manufactured (CM) reference alloy batch to retain the chemical composition and minimize batch-to-batch variation. The AM alloy developed subsurface porosity during oxidation, but the intergranular voids remained closed and unoxidized because of good adhesion of the Cr2O3 scale to the metal. Contrary to many literature studies, AM had no effect on either the oxide growth kinetics or the oxide adherence. The chemical composition of the currently studied AM alloy close to the CM, especially the minor elements e.g. Al, Mn, Si and Ti, is believed to be the key factor preventing oxide decohesion and intergranular oxidation attack.
{"title":"Does additive manufacturing cause intergranular oxidation attack in high-temperature alloys? Case study of Ni-base alloy IN625","authors":"A. Chyrkin , J.-P. Roth , D. Naumenko , K. Jahns","doi":"10.1016/j.corsci.2025.113588","DOIUrl":"10.1016/j.corsci.2025.113588","url":null,"abstract":"<div><div>High-temperature oxidation of additively manufactured (AM) Ni-base alloy IN625 has been studied in air and Ar-4 %H<sub>2</sub>-2 %H<sub>2</sub>O for up to 1000 h at 900 and 1000 °C. AM was produced from the same conventionally manufactured (CM) reference alloy batch to retain the chemical composition and minimize batch-to-batch variation. The AM alloy developed subsurface porosity during oxidation, but the intergranular voids remained closed and unoxidized because of good adhesion of the Cr<sub>2</sub>O<sub>3</sub> scale to the metal. Contrary to many literature studies, AM had no effect on either the oxide growth kinetics or the oxide adherence. The chemical composition of the currently studied AM alloy close to the CM, especially the minor elements e.g. Al, Mn, Si and Ti, is believed to be the key factor preventing oxide decohesion and intergranular oxidation attack.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113588"},"PeriodicalIF":7.4,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-29DOI: 10.1016/j.corsci.2025.113584
Jiantao Qi , Yonghao Liu , Dapeng Wang , Xu Liu , Jizhou Duan
Aviation coatings are critical for aircraft survivability but are prone to degradation in harsh marine environments. Conventional detection methods are limited by subjectivity, low sensitivity to early molecular changes, and the inability to non-destructively assess subsurface integrity. In this work, for the first time, we introduce a machine learning (ML) enhanced Raman spectroscopy framework for the rapid, non-destructive, and intelligent identification of aviation coating damage. We first established the ground-truth degradation pathway of a complex three-layer (Fe-rich/Cu-Ag/SrCrO4-TiO2) coating system via accelerated corrosion testing, where electrochemical impedance spectroscopy confirmed a catastrophic drop in coating resistance (from 7.0 ×103–1.1 ×102 kΩ·cm2). Raman analysis successfully identified the specific chemical signatures of corrosion products, including Fe3O4, α-Fe2O3, Cu2O, and Cr2O3. Leveraging this data, three ML algorithms were trained and one-dimensional convolutional neural network was demonstrated exceptional performance, achieving > 98.9 % accuracy in the complex tasks of identifying material compositions, distinguishing corrosion states, and classifying coating types. Furthermore, by employing feature importance analysis, we opened the “black box” of the model, verifying that its decisions are driven by chemically meaningful spectral features rather than spurious correlations. This work not only provides a powerful diagnostic tool but also establishes a clear methodology for developing field-deployable, intelligent spectroscopic systems for predictive maintenance, promising to enhance the safety and efficiency of aviation asset management.
{"title":"Machine learning-enhanced Raman spectroscopy for rapid identification of aviation coating damage","authors":"Jiantao Qi , Yonghao Liu , Dapeng Wang , Xu Liu , Jizhou Duan","doi":"10.1016/j.corsci.2025.113584","DOIUrl":"10.1016/j.corsci.2025.113584","url":null,"abstract":"<div><div>Aviation coatings are critical for aircraft survivability but are prone to degradation in harsh marine environments. Conventional detection methods are limited by subjectivity, low sensitivity to early molecular changes, and the inability to non-destructively assess subsurface integrity. In this work, for the first time, we introduce a machine learning (ML) enhanced Raman spectroscopy framework for the rapid, non-destructive, and intelligent identification of aviation coating damage. We first established the ground-truth degradation pathway of a complex three-layer (Fe-rich/Cu-Ag/SrCrO<sub>4</sub>-TiO<sub>2</sub>) coating system via accelerated corrosion testing, where electrochemical impedance spectroscopy confirmed a catastrophic drop in coating resistance (from 7.0 ×10<sup>3</sup>–1.1 ×10<sup>2</sup> kΩ·cm<sup>2</sup>). Raman analysis successfully identified the specific chemical signatures of corrosion products, including Fe<sub>3</sub>O<sub>4</sub>, α-Fe<sub>2</sub>O<sub>3</sub>, Cu<sub>2</sub>O, and Cr<sub>2</sub>O<sub>3</sub>. Leveraging this data, three ML algorithms were trained and one-dimensional convolutional neural network was demonstrated exceptional performance, achieving > 98.9 % accuracy in the complex tasks of identifying material compositions, distinguishing corrosion states, and classifying coating types. Furthermore, by employing feature importance analysis, we opened the “black box” of the model, verifying that its decisions are driven by chemically meaningful spectral features rather than spurious correlations. This work not only provides a powerful diagnostic tool but also establishes a clear methodology for developing field-deployable, intelligent spectroscopic systems for predictive maintenance, promising to enhance the safety and efficiency of aviation asset management.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113584"},"PeriodicalIF":7.4,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-28DOI: 10.1016/j.corsci.2025.113585
Mingzheng Hua , Yuan-Hao Zhu , Feng Yang , Mei Chen , Yang Zhao
Marine metal corrosion protection is vital to economic development, yet conventional cathodic protection (CP) suffers from high energy consumption, high cost, and limited power supply. Triboelectric nanogenerator (TENG)-driven self-powered CP has emerged, but humidity-induced surface charge dissipation in seawater limits its long-term stability. Piezoelectric nanogenerators (PENGs), whose output is far less sensitive to humidity, offer a robust route for marine CP, yet their advantages have not been systematically implemented in cathodic protection systems. Here we propose and experimentally validate a water-flow-driven PZT-based PENG concept for marine CP. The PENG converts “blue energy” into electricity, delivering ∼4 V and 20 μA under water-flow impact and maintaining stable output over 24 h in high humidity. After full-bridge rectification, the PENG serves as an effective DC source that charges microfarad-scale capacitors and drives impressed-current CP of iron, achieving a ∼170 mV negative shift in corrosion potential, a 71.2 % decrease in corrosion current density, and lower charge-transfer resistance. This humidity-robust, zero-additional-energy strategy couples piezoelectric energy harvesting with corrosion protection and offers a scalable route to cathodic protection of ships, offshore platforms, and subsea pipelines.
{"title":"Self-powered cathodic protection of marine steel by piezoelectric nanogenerators","authors":"Mingzheng Hua , Yuan-Hao Zhu , Feng Yang , Mei Chen , Yang Zhao","doi":"10.1016/j.corsci.2025.113585","DOIUrl":"10.1016/j.corsci.2025.113585","url":null,"abstract":"<div><div>Marine metal corrosion protection is vital to economic development, yet conventional cathodic protection (CP) suffers from high energy consumption, high cost, and limited power supply. Triboelectric nanogenerator (TENG)-driven self-powered CP has emerged, but humidity-induced surface charge dissipation in seawater limits its long-term stability. Piezoelectric nanogenerators (PENGs), whose output is far less sensitive to humidity, offer a robust route for marine CP, yet their advantages have not been systematically implemented in cathodic protection systems. Here we propose and experimentally validate a water-flow-driven PZT-based PENG concept for marine CP. The PENG converts “blue energy” into electricity, delivering ∼4 V and 20 μA under water-flow impact and maintaining stable output over 24 h in high humidity. After full-bridge rectification, the PENG serves as an effective DC source that charges microfarad-scale capacitors and drives impressed-current CP of iron, achieving a ∼170 mV negative shift in corrosion potential, a 71.2 % decrease in corrosion current density, and lower charge-transfer resistance. This humidity-robust, zero-additional-energy strategy couples piezoelectric energy harvesting with corrosion protection and offers a scalable route to cathodic protection of ships, offshore platforms, and subsea pipelines.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113585"},"PeriodicalIF":7.4,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-28DOI: 10.1016/j.corsci.2025.113586
Hairong Mao , Fuhao Cheng , Donald B. Dingwell , Wenjia Song
Environmental silicate deposits are among the most critical factors driving high-temperature degradation of thermal barrier ceramics, yet the intrinsic corrosion mechanisms remain insufficiently understood. Rare-earth zirconates (RE2Zr2O7) have emerged as promising next-generation candidates, but their resistance to molten silicate attack varies widely with the choice of rare earths. Here, we systematically investigate 15 RE2Zr2O7 compositions based on La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu, and Sc. High-temperature wetting and long-term corrosion experiments at 1300 °C reveal a multivariate dependence of molten silicate spreading and degradation on RE ionic radius, which we examine in terms of lattice energy, RE–O bond ionicity, optical basicity, apatite formation enthalpy, and RE content in fluorite products. Two distinct corrosion modes can be identified: exemplified by exhibits dissolution-controlled interfaces lacking protective barriers (e.g., Tm zirconates) and precipitation-controlled interfaces composed of either dense RE/Ca-apatite/fluorite (e.g., La zirconates) or Sc-garnet layers (Sc zirconates) that act as protective barriers. These results elucidate the fundamental role of rare-earth chemistry in CMAS reactivity and provide mechanistic guidance for designing compositionally optimized (high-entropy) zirconates with superior environmental durability for advanced aero-engine and gas turbine applications.
{"title":"Rare-earth zirconates against environmental silicate corrosion in jet engines","authors":"Hairong Mao , Fuhao Cheng , Donald B. Dingwell , Wenjia Song","doi":"10.1016/j.corsci.2025.113586","DOIUrl":"10.1016/j.corsci.2025.113586","url":null,"abstract":"<div><div>Environmental silicate deposits are among the most critical factors driving high-temperature degradation of thermal barrier ceramics, yet the intrinsic corrosion mechanisms remain insufficiently understood. Rare-earth zirconates (RE<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub>) have emerged as promising next-generation candidates, but their resistance to molten silicate attack varies widely with the choice of rare earths. Here, we systematically investigate 15 RE<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> compositions based on La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu, and Sc. High-temperature wetting and long-term corrosion experiments at 1300 °C reveal a multivariate dependence of molten silicate spreading and degradation on RE ionic radius, which we examine in terms of lattice energy, RE–O bond ionicity, optical basicity, apatite formation enthalpy, and RE content in fluorite products. Two distinct corrosion modes can be identified: exemplified by exhibits dissolution-controlled interfaces lacking protective barriers (e.g., Tm zirconates) and precipitation-controlled interfaces composed of either dense RE/Ca-apatite/fluorite (e.g., La zirconates) or Sc-garnet layers (Sc zirconates) that act as protective barriers. These results elucidate the fundamental role of rare-earth chemistry in CMAS reactivity and provide mechanistic guidance for designing compositionally optimized (high-entropy) zirconates with superior environmental durability for advanced aero-engine and gas turbine applications.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113586"},"PeriodicalIF":7.4,"publicationDate":"2025-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-27DOI: 10.1016/j.corsci.2025.113583
Jiahui Ma , Yating Huang , Jie Cheng , Qinhua Miao , Jinchi Chen , Shirong Ge
Cu and Co serve as interconnect metals in back-end-of-line (BEOL) integrated circuit fabrication. Chemical mechanical polishing (CMP) achieves planarization through chemical oxidation and dissolution by slurry components, which inevitably causes excessive corrosion and surface defects. Consequently, a critical aspect of metal CMP slurry engineering involves suppressing surface defects from both electrochemical and triboelectrochemical effects. Selecting effective corrosion inhibitors is crucial for optimizing both material removal rate and surface quality. In this work, typical azole inhibitor 1, 2, 4-triazaole (TAZ) was systematically evaluated for both the Cu and Co polishing slurries. Corrosion kinetics and thermodynamic parameters were determined by analyzing temperature-dependent corrosion current density variations. Electrochemical results demonstrate that TAZ significantly elevates apparent corrosion activation energies from 13.84 to 20.98 kJ·mol⁻¹ for Co and 13.51–44.78 kJ·mol⁻¹ for Cu, while achieving superior inhibition efficiency for Cu (η = 80.97 % at 2 mM) compared to Co (η = 30.68 % at 10 mM). KPFM and DFT calculations confirm substantially increased work function on Cu surfaces even at low TAZ concentrations. Moreover, triboelectrochemical measurements reveal divergent friction-driven mechanisms where mechanical action enhances cathodic processes on Co, shown by positive OCP shifts, but promoting anodic dissolution on Cu through negative OCP shifts. TAZ effectively mitigates tribocorrosion by forming lubricating adsorption layers that reduce coefficients of friction by over 40 % and suppress material loss. These insights provide a fundamental basis for the rational screening and selection of inhibitors optimized for dynamic CMP conditions.
{"title":"In-depth understanding of the corrosion mechanisms of Co and Cu in chemical mechanical polishing (CMP): Insights from electrochemistry and triboelectrochemistry","authors":"Jiahui Ma , Yating Huang , Jie Cheng , Qinhua Miao , Jinchi Chen , Shirong Ge","doi":"10.1016/j.corsci.2025.113583","DOIUrl":"10.1016/j.corsci.2025.113583","url":null,"abstract":"<div><div>Cu and Co serve as interconnect metals in back-end-of-line (BEOL) integrated circuit fabrication. Chemical mechanical polishing (CMP) achieves planarization through chemical oxidation and dissolution by slurry components, which inevitably causes excessive corrosion and surface defects. Consequently, a critical aspect of metal CMP slurry engineering involves suppressing surface defects from both electrochemical and triboelectrochemical effects. Selecting effective corrosion inhibitors is crucial for optimizing both material removal rate and surface quality. In this work, typical azole inhibitor 1, 2, 4-triazaole (TAZ) was systematically evaluated for both the Cu and Co polishing slurries. Corrosion kinetics and thermodynamic parameters were determined by analyzing temperature-dependent corrosion current density variations. Electrochemical results demonstrate that TAZ significantly elevates apparent corrosion activation energies from 13.84 to 20.98 kJ·mol⁻¹ for Co and 13.51–44.78 kJ·mol⁻¹ for Cu, while achieving superior inhibition efficiency for Cu (<em>η</em> = 80.97 % at 2 mM) compared to Co (<em>η</em> = 30.68 % at 10 mM). KPFM and DFT calculations confirm substantially increased work function on Cu surfaces even at low TAZ concentrations. Moreover, triboelectrochemical measurements reveal divergent friction-driven mechanisms where mechanical action enhances cathodic processes on Co, shown by positive OCP shifts, but promoting anodic dissolution on Cu through negative OCP shifts. TAZ effectively mitigates tribocorrosion by forming lubricating adsorption layers that reduce coefficients of friction by over 40 % and suppress material loss. These insights provide a fundamental basis for the rational screening and selection of inhibitors optimized for dynamic CMP conditions.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113583"},"PeriodicalIF":7.4,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-27DOI: 10.1016/j.corsci.2025.113587
Farzad Jafarihonar , Alessandro Ruozzi , Hanna Kinnunen , Leena Hupa , Emil Vainio
This study investigates the risk of low-temperature corrosion on carbon steel tube surfaces located at the clean side of the flue gas channel downstream of a selective catalytic reduction (SCR) unit in a full-scale bubbling fluidized bed (BFB) boiler, where the HCl(g) concentration is typically very low (<5 ppmv). Short- and long-term corrosion probe measurements, along with online deposit monitoring, were carried out in the flue gas channel to determine the causes of corrosion and establish safe material temperatures. To further investigate the results, laboratory tests were conducted in a quartz-tube furnace under simulated flue gas conditions. The results demonstrated that corrosion rates increased once the material surface temperature fell below 90 °C, with particularly severe attack evident at 80 and 70 °C. Notably, a considerable amount of chlorine was present in the corrosion products, indicating a high risk of chlorine-induced corrosion at cold-end surfaces, even at very low HCl(g) concentrations. Two potential corrosion mechanisms were identified, namely the absorption of HCl(g) into surface-adsorbed water monolayers above the water dew point, and the presence of corrosive NH4Cl(s,aq) on tube surfaces. HCl-induced corrosion was found to be the most likely mechanism. According to this mechanism, corrosion can occur even without bulk water condensation, and it depends on the local relative humidity (RH) at the steel surface. The findings collectively suggest that carbon steel surfaces on the clean side of the flue gas path should be maintained above approximately 90 °C (with an appropriate safety margin, depending on flue gas H2O(g) concentration) to mitigate the observed HCl-induced corrosion. A similar corrosion mechanism may also affect the dirty side of the flue gas path at similarly low temperatures.
{"title":"New insights into HCl-induced low-temperature corrosion in biomass- and waste-fired boilers","authors":"Farzad Jafarihonar , Alessandro Ruozzi , Hanna Kinnunen , Leena Hupa , Emil Vainio","doi":"10.1016/j.corsci.2025.113587","DOIUrl":"10.1016/j.corsci.2025.113587","url":null,"abstract":"<div><div>This study investigates the risk of low-temperature corrosion on carbon steel tube surfaces located at the clean side of the flue gas channel downstream of a selective catalytic reduction (SCR) unit in a full-scale bubbling fluidized bed (BFB) boiler, where the HCl(g) concentration is typically very low (<5 ppm<sub>v</sub>). Short- and long-term corrosion probe measurements, along with online deposit monitoring, were carried out in the flue gas channel to determine the causes of corrosion and establish safe material temperatures. To further investigate the results, laboratory tests were conducted in a quartz-tube furnace under simulated flue gas conditions. The results demonstrated that corrosion rates increased once the material surface temperature fell below 90 °C, with particularly severe attack evident at 80 and 70 °C. Notably, a considerable amount of chlorine was present in the corrosion products, indicating a high risk of chlorine-induced corrosion at cold-end surfaces, even at very low HCl(g) concentrations. Two potential corrosion mechanisms were identified, namely the absorption of HCl(g) into surface-adsorbed water monolayers above the water dew point, and the presence of corrosive NH<sub>4</sub>Cl(s,aq) on tube surfaces. HCl-induced corrosion was found to be the most likely mechanism. According to this mechanism, corrosion can occur even without bulk water condensation, and it depends on the local relative humidity (RH) at the steel surface. The findings collectively suggest that carbon steel surfaces on the clean side of the flue gas path should be maintained above approximately 90 °C (with an appropriate safety margin, depending on flue gas H<sub>2</sub>O(g) concentration) to mitigate the observed HCl-induced corrosion. A similar corrosion mechanism may also affect the dirty side of the flue gas path at similarly low temperatures.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"261 ","pages":"Article 113587"},"PeriodicalIF":7.4,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-26DOI: 10.1016/j.corsci.2025.113582
Joseph C. Doyle , Edward A. Saunders , Jane M. Woolrich , Mark E. Light , Nong Gao , Philippa A.S. Reed
The oxidation behaviours of three different generations of single crystal Ni-based superalloys (SRR-99 – 1st generation, CMSX-4 – 2nd generation, and CMSX-10N – 3rd generation) have been investigated and compared at 550 °C. Isothermal oxidation tests were carried out at various exposure times ranging from 2 h up to 1000 h and it was found that oxide morphology and development showed noticeable differences between the alloys. Scanning electron microscopy (SEM), 3D imaging reconstruction, energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were employed to characterise the oxide scales. The external and internal oxides were studied through high-resolution imaging, measurements from which revealed the oxidation kinetics of CMSX-4 and CMSX-10N followed a near-parabolic law whilst a logarithmic law better described the kinetics behaviour of SRR-99. Thermodynamic modelling was used to predict the species and composition of oxides formed in each alloy and compared to measured EDS and XRD results. From the experimental results and modelling, it was found that the mechanism and oxide products formed for CMSX-4 and CMSX-10N are very similar, as NiO initially formed externally over the γ channels and the γ’ precipitates were preferentially oxidised internally at the γ/γ’ interface.
{"title":"Comparing the oxidation behaviour of three generations of single crystal nickel-based superalloys at an intermediate service temperature","authors":"Joseph C. Doyle , Edward A. Saunders , Jane M. Woolrich , Mark E. Light , Nong Gao , Philippa A.S. Reed","doi":"10.1016/j.corsci.2025.113582","DOIUrl":"10.1016/j.corsci.2025.113582","url":null,"abstract":"<div><div>The oxidation behaviours of three different generations of single crystal Ni-based superalloys (SRR-99 – 1st generation, CMSX-4 – 2nd generation, and CMSX-10N – 3rd generation) have been investigated and compared at 550 °C. Isothermal oxidation tests were carried out at various exposure times ranging from 2 h up to 1000 h and it was found that oxide morphology and development showed noticeable differences between the alloys. Scanning electron microscopy (SEM), 3D imaging reconstruction, energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were employed to characterise the oxide scales. The external and internal oxides were studied through high-resolution imaging, measurements from which revealed the oxidation kinetics of CMSX-4 and CMSX-10N followed a near-parabolic law whilst a logarithmic law better described the kinetics behaviour of SRR-99. Thermodynamic modelling was used to predict the species and composition of oxides formed in each alloy and compared to measured EDS and XRD results. From the experimental results and modelling, it was found that the mechanism and oxide products formed for CMSX-4 and CMSX-10N are very similar, as NiO initially formed externally over the γ channels and the γ’ precipitates were preferentially oxidised internally at the γ/γ’ interface.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"261 ","pages":"Article 113582"},"PeriodicalIF":7.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145897966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-26DOI: 10.1016/j.corsci.2025.113579
Junjie Hao , Chuanyi Chen , Peng Xue , Bo Chen , Lei Shu , Mengshu Zhang , Hongzhi Niu , Xiaobing Li , Kui Liu
Heat-treated Ti-44Al-3Mn-0.4Mo-0.4W-0.1B-0.1 C alloy with near-lamellar (NL) and equiaxed microstructures (EQ) underwent 100-hour cyclic oxidation at 750/800 °C and 100–3000 h isothermal oxidation at 750 °C. The microstructural evolution and oxidation behavior were characterized using SEM, EPMA, EBSD, EDS, XRD, and TEM. Results demonstrate that the oxidation kinetics of both microstructures approximately follow near-linear law during cyclic oxidation. The surface oxidation products primarily consist of a mixture of rutile and α-Al2O3, accompanied by minor amounts of TiNxOy (fcc) and α-Mn2O3. The EQ microstructure exhibits marginally superior oxidation resistance compared to the NL microstructure, with both forming intact oxide scales devoid of cracking or spallation. The transition layer primarily consists of Laves phases with minor βo phases. Notably, under long-term isothermal oxidation, the NL microstructure demonstrates significantly enhanced oxidation resistance compared to the EQ structure. Phase transformation near the oxide layer in the NL structure generates a diffusion zone comprising (βo+γ+Laves) phases. This transformation facilitates the formation of a dense and structurally coherent transition layer with reduced βo phase content, effectively suppressing outward Mn diffusion and substantially improving oxidation resistance. Conversely, the EQ microstructure shows no significant phase transformation near the oxide layer. Abundant βo phases were found in the transition layer that compromise structural integrity, resulting in inferior oxidation performance.
{"title":"Microstructure-dependent high-temperature oxidation behavior of Mn-Containing β-solidifying γ-TiAl alloys","authors":"Junjie Hao , Chuanyi Chen , Peng Xue , Bo Chen , Lei Shu , Mengshu Zhang , Hongzhi Niu , Xiaobing Li , Kui Liu","doi":"10.1016/j.corsci.2025.113579","DOIUrl":"10.1016/j.corsci.2025.113579","url":null,"abstract":"<div><div>Heat-treated Ti-44Al-3Mn-0.4Mo-0.4W-0.1B-0.1 C alloy with near-lamellar (NL) and equiaxed microstructures (EQ) underwent 100-hour cyclic oxidation at 750/800 °C and 100–3000 h isothermal oxidation at 750 °C. The microstructural evolution and oxidation behavior were characterized using SEM, EPMA, EBSD, EDS, XRD, and TEM. Results demonstrate that the oxidation kinetics of both microstructures approximately follow near-linear law during cyclic oxidation. The surface oxidation products primarily consist of a mixture of rutile and α-Al<sub>2</sub>O<sub>3</sub>, accompanied by minor amounts of TiN<sub>x</sub>O<sub>y</sub> (fcc) and α-Mn<sub>2</sub>O<sub>3</sub>. The EQ microstructure exhibits marginally superior oxidation resistance compared to the NL microstructure, with both forming intact oxide scales devoid of cracking or spallation. The transition layer primarily consists of Laves phases with minor β<sub>o</sub> phases. Notably, under long-term isothermal oxidation, the NL microstructure demonstrates significantly enhanced oxidation resistance compared to the EQ structure. Phase transformation near the oxide layer in the NL structure generates a diffusion zone comprising (β<sub>o</sub>+γ+Laves) phases. This transformation facilitates the formation of a dense and structurally coherent transition layer with reduced β<sub>o</sub> phase content, effectively suppressing outward Mn diffusion and substantially improving oxidation resistance. Conversely, the EQ microstructure shows no significant phase transformation near the oxide layer. Abundant β<sub>o</sub> phases were found in the transition layer that compromise structural integrity, resulting in inferior oxidation performance.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113579"},"PeriodicalIF":7.4,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145880013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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