Pub Date : 2025-12-13DOI: 10.1016/j.corsci.2025.113553
Fengwei Xie , Ziren Yuan , Luli Feng , Shuaipeng Chen , Ziyi Xu , Yuehui He , Xiyue Kang
Minor silicon addition to carbon-free Fe-Co-Mo high-speed steels markedly enhances the oxidation resistance, quantitatively demonstrated by an increase in the apparent oxidation activation energy from 161.1 kJ/mol (Si-free) to 212.5 kJ/mol (0.5 wt% Si). This enhancement is rooted in a novel mechanism of the dual role of Si. Initially, Si addition tailors the microstructure by refining grain and promoting Si-rich Laves phases that serve as internal reservoirs. Subsequently, these reservoirs enable the in-situ formation of a nano-dispersed amorphous SiO2 network along critical diffusion pathways during oxidation. This internal barrier not only effectively impedes ion transport but also dynamically induces the transformation of the Laves phase into Si-depleted R and µ phases. This “beneficial internal oxidation” strategy presents a new paradigm for designing advanced oxidation-resistant alloys, distinct from classical external scale formation.
{"title":"Elucidating the minor Si-driven internal barrier mechanism for enhanced oxidation resistance of carbon-free high-speed steels","authors":"Fengwei Xie , Ziren Yuan , Luli Feng , Shuaipeng Chen , Ziyi Xu , Yuehui He , Xiyue Kang","doi":"10.1016/j.corsci.2025.113553","DOIUrl":"10.1016/j.corsci.2025.113553","url":null,"abstract":"<div><div>Minor silicon addition to carbon-free Fe-Co-Mo high-speed steels markedly enhances the oxidation resistance, quantitatively demonstrated by an increase in the apparent oxidation activation energy from 161.1 kJ/mol (Si-free) to 212.5 kJ/mol (0.5 wt% Si). This enhancement is rooted in a novel mechanism of the dual role of Si. Initially, Si addition tailors the microstructure by refining grain and promoting Si-rich Laves phases that serve as internal reservoirs. Subsequently, these reservoirs enable the in-situ formation of a nano-dispersed amorphous SiO<sub>2</sub> network along critical diffusion pathways during oxidation. This internal barrier not only effectively impedes ion transport but also dynamically induces the transformation of the Laves phase into Si-depleted R and µ phases. This “beneficial internal oxidation” strategy presents a new paradigm for designing advanced oxidation-resistant alloys, distinct from classical external scale formation.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113553"},"PeriodicalIF":7.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787249","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 : 2025-12-13DOI: 10.1016/j.corsci.2025.113556
Yiqi Zhou, Zhigang Yang, Chi Zhang
This study elucidates the roles of Mo and N in the pitting corrosion of lean duplex stainless steels (LDSS) 2101 (0.3 % Mo, 0.21 % N) and LDSS 2001 (0 % Mo, 0.13 % N). The synergistic addition of Mo and N in LDSS 2001 enhances passive film stability in NaCl solution, resulting in a critical pitting potential (Epit) of 0.32 VSCE, which is higher than the 0.24 VSCE measured for LDSS 2101. In NaBr, however, the Epit values become similar, ranging from 0.33 to 0.35 VSCE for both grades. Bipolar electrochemistry measurements quantified the corrosion volume loss, with the highest value of 2.73 × 109 μm3 observed for LDSS 2001 in NaCl, with corrosion volume loss was 2.61 × 109 μm3 in NaBr. For LDSS 2101, the corrosion volume loss was 2.62 × 109 μm3 in NaCl and 7.02 × 108 μm3 in NaBr. Here, a faster corrosion growth rate indicates larger corrosion volumes. Pit nucleated in the ferrite phase for LDSS 2001. In NaCl, the austenite phase in LDSS 2101 was the pit nucleation site. In NaBr, LDSS 2101 exhibited a transition from ferrite-nucleated pitting at low potentials to both phases being attacked by pitting at high potentials. These results underscore a fundamental shift in the micro-electrochemical stability of the constituent phases, governed by the interplay between alloying elements and halide ions.
{"title":"Synergistic Mo and N effects on pitting corrosion of lean duplex stainless steels: A fundamental shift in phase-dependent stability in halide environments","authors":"Yiqi Zhou, Zhigang Yang, Chi Zhang","doi":"10.1016/j.corsci.2025.113556","DOIUrl":"10.1016/j.corsci.2025.113556","url":null,"abstract":"<div><div>This study elucidates the roles of Mo and N in the pitting corrosion of lean duplex stainless steels (LDSS) 2101 (0.3 % Mo, 0.21 % N) and LDSS 2001 (0 % Mo, 0.13 % N). The synergistic addition of Mo and N in LDSS 2001 enhances passive film stability in NaCl solution, resulting in a critical pitting potential (<em>E</em><sub><em>pit</em></sub>) of 0.32 V<sub>SCE</sub>, which is higher than the 0.24 V<sub>SCE</sub> measured for LDSS 2101. In NaBr, however, the <em>E</em><sub><em>pit</em></sub> values become similar, ranging from 0.33 to 0.35 V<sub>SCE</sub> for both grades. Bipolar electrochemistry measurements quantified the corrosion volume loss, with the highest value of 2.73 × 10<sup>9</sup> μm<sup>3</sup> observed for LDSS 2001 in NaCl, with corrosion volume loss was 2.61 × 10<sup>9</sup> μm<sup>3</sup> in NaBr. For LDSS 2101, the corrosion volume loss was 2.62 × 10<sup>9</sup> μm<sup>3</sup> in NaCl and 7.02 × 10<sup>8</sup> μm<sup>3</sup> in NaBr. Here, a faster corrosion growth rate indicates larger corrosion volumes. Pit nucleated in the ferrite phase for LDSS 2001. In NaCl, the austenite phase in LDSS 2101 was the pit nucleation site. In NaBr, LDSS 2101 exhibited a transition from ferrite-nucleated pitting at low potentials to both phases being attacked by pitting at high potentials. These results underscore a fundamental shift in the micro-electrochemical stability of the constituent phases, governed by the interplay between alloying elements and halide ions.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113556"},"PeriodicalIF":7.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787251","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}
This investigation studied the potential influence of different amounts of alloying element Cr (0.5, 1.2 and 2.1 wt%) on hydrogen-induced delayed fracture (HIDF) performance of V+Nb-microalloyed high-strength bolt steel with high temperature tempered martensitic microstructure. The HIDF performance was evaluated by slow strain rate tensile (SSRT) tests using pre-hydrogen-charged notched specimens. The results show that the size of re-precipitated plate-like nano-sized V-rich MC carbides slightly decreases with the increase in Cr content, and Cr-rich M7C3 carbides only exist in the steel containing 2.1 wt% Cr. The HIDF resistance represented by notch tensile strength decreases and the tendency to brittle intergranular fracture along notch root region increases with the increase in Cr content. The diffusible hydrogen contents obtained from both the pre-hydrogen-charged and the fractured SSRT specimens exhibit an increasing trend while the effective hydrogen diffusion coefficient decreases with increasing Cr content. The reasons for this adverse effect of increasing Cr content on HIDF performance are explained by the changes of microstructural characteristics and corresponding hydrogen trapping characteristics.
{"title":"Effect of Cr on hydrogen-induced delayed fracture of high-strength bolt steel","authors":"Boyang Fang, Weijun Hui, Zhuo Hua, Yixuan Xu, Yongjian Zhang, Xiaoli Zhao","doi":"10.1016/j.corsci.2025.113533","DOIUrl":"10.1016/j.corsci.2025.113533","url":null,"abstract":"<div><div>This investigation studied the potential influence of different amounts of alloying element Cr (0.5, 1.2 and 2.1 wt%) on hydrogen-induced delayed fracture (HIDF) performance of V+Nb-microalloyed high-strength bolt steel with high temperature tempered martensitic microstructure. The HIDF performance was evaluated by slow strain rate tensile (SSRT) tests using pre-hydrogen-charged notched specimens. The results show that the size of re-precipitated plate-like nano-sized V-rich MC carbides slightly decreases with the increase in Cr content, and Cr-rich M<sub>7</sub>C<sub>3</sub> carbides only exist in the steel containing 2.1 wt% Cr. The HIDF resistance represented by notch tensile strength decreases and the tendency to brittle intergranular fracture along notch root region increases with the increase in Cr content. The diffusible hydrogen contents obtained from both the pre-hydrogen-charged and the fractured SSRT specimens exhibit an increasing trend while the effective hydrogen diffusion coefficient decreases with increasing Cr content. The reasons for this adverse effect of increasing Cr content on HIDF performance are explained by the changes of microstructural characteristics and corresponding hydrogen trapping characteristics.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113533"},"PeriodicalIF":7.4,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734286","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 : 2025-12-12DOI: 10.1016/j.corsci.2025.113550
Chenhui Hu , Chenyu Li , Zhen Zhang , Youjun Ye , Lin Liu
This study systematically investigates the effect of titanium (Ti) ion implantation time on the corrosion and stress corrosion cracking (SCC) resistance of 304 stainless steel in a chloride environment. Corrosion properties and electrochemical behavior were evaluated using weight loss measurements and electrochemical tests, while SCC susceptibility was assessed via slow strain rate tensile (SSRT) tests. Specimen morphologies were examined using metallographic and scanning electron microscopy (SEM), and microstructural features were characterized by transmission electron microscopy (TEM). Chemical composition and states were analyzed using X-ray photoelectron spectroscopy (XPS). The results indicate that a longer Ti ion implantation time leads to a continuous increase in polarization resistance and a higher pitting potential, which implies an improvement in corrosion resistance. In a chloride environment without external tensile stress, the dominant corrosion mode transitions from general corrosion to pitting corrosion, with severity mitigated by extended implantation times. Moreover, SCC susceptibility decreases markedly, particularly when implantation time exceeds 2.0 h, due to the formation of a reinforced titanium-rich surface film containing a high density of twins and dislocations. The increased density of twins and twin boundaries induced by prolonged Ti ion implantation effectively obstructs dislocation slip under tensile stress, thereby inhibiting SCC propagation.
{"title":"Effect of titanium ion implantation time on the corrosion and stress corrosion cracking resistance of 304 stainless steel in a chloride environment","authors":"Chenhui Hu , Chenyu Li , Zhen Zhang , Youjun Ye , Lin Liu","doi":"10.1016/j.corsci.2025.113550","DOIUrl":"10.1016/j.corsci.2025.113550","url":null,"abstract":"<div><div>This study systematically investigates the effect of titanium (Ti) ion implantation time on the corrosion and stress corrosion cracking (SCC) resistance of 304 stainless steel in a chloride environment. Corrosion properties and electrochemical behavior were evaluated using weight loss measurements and electrochemical tests, while SCC susceptibility was assessed via slow strain rate tensile (SSRT) tests. Specimen morphologies were examined using metallographic and scanning electron microscopy (SEM), and microstructural features were characterized by transmission electron microscopy (TEM). Chemical composition and states were analyzed using X-ray photoelectron spectroscopy (XPS). The results indicate that a longer Ti ion implantation time leads to a continuous increase in polarization resistance and a higher pitting potential, which implies an improvement in corrosion resistance. In a chloride environment without external tensile stress, the dominant corrosion mode transitions from general corrosion to pitting corrosion, with severity mitigated by extended implantation times. Moreover, SCC susceptibility decreases markedly, particularly when implantation time exceeds 2.0 h, due to the formation of a reinforced titanium-rich surface film containing a high density of twins and dislocations. The increased density of twins and twin boundaries induced by prolonged Ti ion implantation effectively obstructs dislocation slip under tensile stress, thereby inhibiting SCC propagation.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113550"},"PeriodicalIF":7.4,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787248","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 : 2025-12-12DOI: 10.1016/j.corsci.2025.113551
Haosen Jiang , Zuquan Jin , Shicai Li , Xiaoying Zhang
Cathodic protection (CP) is a commonly used corrosion prevention technique for reinforced concrete structures in marine environments. The applied cathodic current inhibits electron loss from the steel surface. An essential role in evaluating the long-term durability of reinforced concrete in marine environments is played by understanding the formation and protective behavior of passive films (PFs) on steel surfaces under cathodic protection. In this study, the evolution mechanism of PFs on HRB400 steel under CP conditions was systematically investigated via electrochemical techniques in combination with microstructural characterization. It was demonstrated by the results that the initial passivation of steel in concrete was significantly inhibited by CP. The anodic peak corresponding to Fe0→Fe2+ disappeared in the CV curve, and the Fe2+ content of PF under CP conditions was decreased to 0.85 % (vs. 3.44 % under natural passivation (NP) conditions). During NP processes, the PF formed on the steel surface is primarily composed of Fe(OH)2, Fe2O3, and CaFeO2. Under CP conditions, these phases still remain present, and Fe3O4 was additionally observed. In addition, CP the deposition of Ca2+ from the simulated concrete pore solution was facilitated by CP, and the formation of newly emerged phases (including CaFe2O4 and Ca(OH)2) was caused. This compositional transformation was found to reduce the intrinsic barrier properties of the PF, although the overall CP system effectively inhibited corrosion. Novel insights into the mechanistic effects of CP on PF evolution are provided by these findings, and theoretical guidance for optimizing CP strategies in marine reinforced concrete is also offered.
{"title":"Composition-structure-corrosion resistance of steel passive film in concrete under cathodic protection","authors":"Haosen Jiang , Zuquan Jin , Shicai Li , Xiaoying Zhang","doi":"10.1016/j.corsci.2025.113551","DOIUrl":"10.1016/j.corsci.2025.113551","url":null,"abstract":"<div><div>Cathodic protection (CP) is a commonly used corrosion prevention technique for reinforced concrete structures in marine environments. The applied cathodic current inhibits electron loss from the steel surface. An essential role in evaluating the long-term durability of reinforced concrete in marine environments is played by understanding the formation and protective behavior of passive films (PFs) on steel surfaces under cathodic protection. In this study, the evolution mechanism of PFs on HRB400 steel under CP conditions was systematically investigated via electrochemical techniques in combination with microstructural characterization. It was demonstrated by the results that the initial passivation of steel in concrete was significantly inhibited by CP. The anodic peak corresponding to Fe<sup>0</sup>→Fe<sup>2+</sup> disappeared in the CV curve, and the Fe<sup>2+</sup> content of PF under CP conditions was decreased to 0.85 % (vs. 3.44 % under natural passivation (NP) conditions). During NP processes, the PF formed on the steel surface is primarily composed of Fe(OH)<sub>2</sub>, Fe<sub>2</sub>O<sub>3</sub>, and CaFeO<sub>2</sub>. Under CP conditions, these phases still remain present, and Fe<sub>3</sub>O<sub>4</sub> was additionally observed. In addition, CP the deposition of Ca<sup>2+</sup> from the simulated concrete pore solution was facilitated by CP, and the formation of newly emerged phases (including CaFe<sub>2</sub>O<sub>4</sub> and Ca(OH)<sub>2</sub>) was caused. This compositional transformation was found to reduce the intrinsic barrier properties of the PF, although the overall CP system effectively inhibited corrosion. Novel insights into the mechanistic effects of CP on PF evolution are provided by these findings, and theoretical guidance for optimizing CP strategies in marine reinforced concrete is also offered.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113551"},"PeriodicalIF":7.4,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787149","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 : 2025-12-11DOI: 10.1016/j.corsci.2025.113549
L.Z. Kang, Y.H. Lu, Z.J. Shi, Y.M. Han, L. Xin
The effect of dissolved hydrogen (DH) on the fretting corrosion of Zr-alloy under different fretting regimes in high temperature pressurised water was investigated. The results indicated that the effect of DH on fretting corrosion of Zr-alloy depended on the fretting regime. Under partial slip regime (PSR) and mixed fretting regime (MFR), the main damage mechanism was fretting corrosion cracks, introduction of 2.5 ppm DH had a negligible effect on fretting corrosion behavior and did not change damage mechanism. Under gross slip regime (GSR), the main damage mechanisms without DH were adhesive wear, oxidation, and delamination. Introduction of 2.5 ppm DH caused a significant increase in wear volume and changed damage mechanisms to adhesive wear, oxidation and fretting corrosion cracks. Introduction of 2.5 ppm DH reduced the formation of NiCr2O4 and introduced a small amount of Cr2O3 in TBL, which resulted in less formation of the protective TBL under GSR and thereby promoted fretting corrosion.
{"title":"Influence of dissolved hydrogen on the fretting corrosion of zirconium alloy under different fretting regimes in high temperature pressurised water environment","authors":"L.Z. Kang, Y.H. Lu, Z.J. Shi, Y.M. Han, L. Xin","doi":"10.1016/j.corsci.2025.113549","DOIUrl":"10.1016/j.corsci.2025.113549","url":null,"abstract":"<div><div>The effect of dissolved hydrogen (DH) on the fretting corrosion of Zr-alloy under different fretting regimes in high temperature pressurised water was investigated. The results indicated that the effect of DH on fretting corrosion of Zr-alloy depended on the fretting regime. Under partial slip regime (PSR) and mixed fretting regime (MFR), the main damage mechanism was fretting corrosion cracks, introduction of 2.5 ppm DH had a negligible effect on fretting corrosion behavior and did not change damage mechanism. Under gross slip regime (GSR), the main damage mechanisms without DH were adhesive wear, oxidation, and delamination. Introduction of 2.5 ppm DH caused a significant increase in wear volume and changed damage mechanisms to adhesive wear, oxidation and fretting corrosion cracks. Introduction of 2.5 ppm DH reduced the formation of NiCr<sub>2</sub>O<sub>4</sub> and introduced a small amount of Cr<sub>2</sub>O<sub>3</sub> in TBL, which resulted in less formation of the protective TBL under GSR and thereby promoted fretting corrosion.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113549"},"PeriodicalIF":7.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734287","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}
The multi-layer oxides formed on surfaces of nickel-based single crystal superalloys are well-documented, yet their precise formation scenarios remain uncovered, since a fine time series of microstructural observations of their dynamic evolution in early-stage oxidation has never been accomplished. Here, we report a refined formation scenario of these oxide sub-layers in a second-generation nickel-based single crystal superalloy. Our findings demonstrate that there are actually 5 distinct oxide sub-layers formed on surface, which are identified respectively as the 1st (Ni0.9Co0.1)O, 2nd NiAl₂O₄, 3rd CoCr₂O₄, 4th CrTaO₄, and 5th Al₂O₃ sub-layers. However, their temporal formation sequence or scenario differs from their spatial formation sequence: the 5th secondary Al₂O₃ sub-layers appear before formation of the 2nd, 3rd and 4th oxide sub-layers. Notably, upon oxidation γ-phase areas act as preferential pathways for in-depth oxygen diffusion, facilitating the innermost 5th secondary Al₂O₃ sub-layer to form. Our study provides in-depth insights into a high-temperature oxidation mechanism of superalloys.
{"title":"A refined formation scenario of high-temperature oxide sub-layers in nickel-based single crystal superalloys","authors":"Zhiqiang Zhou , Pan Xie , Cuilan Wu , Jianghua Chen","doi":"10.1016/j.corsci.2025.113548","DOIUrl":"10.1016/j.corsci.2025.113548","url":null,"abstract":"<div><div>The multi-layer oxides formed on surfaces of nickel-based single crystal superalloys are well-documented, yet their precise formation scenarios remain uncovered, since a fine time series of microstructural observations of their dynamic evolution in early-stage oxidation has never been accomplished. Here, we report a refined formation scenario of these oxide sub-layers in a second-generation nickel-based single crystal superalloy. Our findings demonstrate that there are actually 5 distinct oxide sub-layers formed on surface, which are identified respectively as the 1st (Ni<sub>0.9</sub>Co<sub>0.1</sub>)O, 2nd NiAl₂O₄, 3rd CoCr₂O₄, 4th CrTaO₄, and 5th Al₂O₃ sub-layers. However, their temporal formation sequence or scenario differs from their spatial formation sequence: the 5th secondary Al₂O₃ sub-layers appear before formation of the 2nd, 3rd and 4th oxide sub-layers. Notably, upon oxidation γ-phase areas act as preferential pathways for in-depth oxygen diffusion, facilitating the innermost 5th secondary Al₂O₃ sub-layer to form. Our study provides in-depth insights into a high-temperature oxidation mechanism of superalloys.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113548"},"PeriodicalIF":7.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734288","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 : 2025-12-10DOI: 10.1016/j.corsci.2025.113545
Jifeng Li , Guanhong Lei , Jiupeng Song , Shuai Yan , Qian Xiao , Xiang-Xi Ye
A systematic study was conducted on the high-temperature oxidation process of WC-Ni cemented carbide at 700 °C, with a particular focus on the influences of Ni content (ranging from 0.5 wt% to 50 wt%) and the addition of Nb and Cr. The oxidation kinetics of all samples followed a linear rate law, and the oxidation resistance improved with increasing Ni content. However, higher Ni concentrations also promoted the formation of NiWO₄, resulting in a more porous and friable oxide scale. The addition of Cr consistently enhanced the oxidation resistance of both WC10Ni and WC30Ni alloys. Synchrotron X-ray absorption spectroscopy confirmed that Cr dissolved into the NiWO₄ lattice as Cr³⁺, where its substitution for Ni²⁺ reduced the concentration of oxygen vacancies, thereby inhibiting the ion transport. In contrast, Nb plays a complex dual role. The preferential oxidation of NbC clusters generated porous Nb₂O₅, damaging the integrity of the scale, which had a detrimental effect on the WC10Ni alloy. Concurrently, Nb dissolved into the NiWO₄ phase, where its higher valence state (between +2 and +4) suppressed oxygen vacancies, which was beneficial. The latter mechanism prevails in the WC30Ni alloy, resulting in a net improvement in oxidation resistance.
{"title":"Effect of Ni content and Nb, Cr doping on the oxidation behavior of WC-Ni cemented carbide at 700 °C","authors":"Jifeng Li , Guanhong Lei , Jiupeng Song , Shuai Yan , Qian Xiao , Xiang-Xi Ye","doi":"10.1016/j.corsci.2025.113545","DOIUrl":"10.1016/j.corsci.2025.113545","url":null,"abstract":"<div><div>A systematic study was conducted on the high-temperature oxidation process of WC-Ni cemented carbide at 700 °C, with a particular focus on the influences of Ni content (ranging from 0.5 wt% to 50 wt%) and the addition of Nb and Cr. The oxidation kinetics of all samples followed a linear rate law, and the oxidation resistance improved with increasing Ni content. However, higher Ni concentrations also promoted the formation of NiWO₄, resulting in a more porous and friable oxide scale. The addition of Cr consistently enhanced the oxidation resistance of both WC10Ni and WC30Ni alloys. Synchrotron X-ray absorption spectroscopy confirmed that Cr dissolved into the NiWO₄ lattice as Cr³⁺, where its substitution for Ni²⁺ reduced the concentration of oxygen vacancies, thereby inhibiting the ion transport. In contrast, Nb plays a complex dual role. The preferential oxidation of NbC clusters generated porous Nb₂O₅, damaging the integrity of the scale, which had a detrimental effect on the WC10Ni alloy. Concurrently, Nb dissolved into the NiWO₄ phase, where its higher valence state (between +2 and +4) suppressed oxygen vacancies, which was beneficial. The latter mechanism prevails in the WC30Ni alloy, resulting in a net improvement in oxidation resistance.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113545"},"PeriodicalIF":7.4,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787250","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 : 2025-12-10DOI: 10.1016/j.corsci.2025.113544
Qifeng Zeng , Shitong Xu , Meiyi Yao , Hanfang Xie , Yunqing Zhou , Qingdong Liu , Shengyi Si , Lefu Zhang , Junqiang Lu , Fuliang Chen
This study investigates the influence of tin content on the uniform and nodular corrosion behavior of novel Nb-free Zr-xSn-0.20Fe-0.18Cr-0.03Ni (x = 1.00, 1.35 wt%) alloys in superheated steam at 400 ℃/10.3 MPa and 500 ℃/10.3 MPa. Microstructural characterization using scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed fully recrystallized matrices with uniformly distributed second phase particles (SPPs), identified as hexagonal close-packed (hcp)-Zr(Fe,Cr)₂ and body-centered tetragonal (bct)-Zr₂(Fe,Ni) types. Higher Tin (Sn) content promoted the precipitation of SPPs and increased microstructural heterogeneity. Corrosion tests demonstrated that the 1.35Sn alloy exhibited accelerated uniform corrosion compared to the 1.00Sn alloy under both conditions, with weight gains approximately 15 % and 40 % higher after 400 d and 1000 h, respectively. However, both alloys completely suppressed nodular corrosion, unlike the reference Zr-4 alloy. This is attributed to the Ni addition, as the resulting NiO exhibits high solubility in the ZrO₂ matrix and a compatible Pilling-Bedworth ratio, which mitigates oxidation-induced stress. X-ray photoelectron spectroscopy (XPS) analysis indicated increased SnO₂ formation in the oxide outer surface and higher degree of oxidation of Fe, Cr, and Ni in the high-Sn alloy, contributing to stress accumulation within the oxide film. Cross-sectional SEM observations revealed a significantly higher density of microcracks in the high-Sn alloy, particularly within the inner columnar grain region. A stress-dominated mechanism is proposed as an alternative to the classical anion-vacancy model, in which Sn-induced volumetric expansion, t-ZrO₂ to m-ZrO₂ phase transformation, and oxidation of SPPs act synergistically to promote microcracking, oxide degradation, and accelerated corrosion. These findings offer new insights into Sn-accelerated corrosion mechanisms and provide a foundation for the further development of Nb-free zirconium alloys with potential for use in demanding environments such as those anticipated in some small modular reactors (SMRs) designs.
{"title":"Corrosion behavior of Zr-xSn-0.20Fe-0.18Cr-0.03Ni alloys in 400 ℃ and 500 ℃ superheated steam","authors":"Qifeng Zeng , Shitong Xu , Meiyi Yao , Hanfang Xie , Yunqing Zhou , Qingdong Liu , Shengyi Si , Lefu Zhang , Junqiang Lu , Fuliang Chen","doi":"10.1016/j.corsci.2025.113544","DOIUrl":"10.1016/j.corsci.2025.113544","url":null,"abstract":"<div><div>This study investigates the influence of tin content on the uniform and nodular corrosion behavior of novel Nb-free Zr-<em>x</em>Sn-0.20Fe-0.18Cr-0.03Ni (<em>x</em> = 1.00, 1.35 wt%) alloys in superheated steam at 400 ℃/10.3 MPa and 500 ℃/10.3 MPa. Microstructural characterization using scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed fully recrystallized matrices with uniformly distributed second phase particles (SPPs), identified as hexagonal close-packed (hcp)-Zr(Fe,Cr)₂ and body-centered tetragonal (bct)-Zr₂(Fe,Ni) types. Higher Tin (Sn) content promoted the precipitation of SPPs and increased microstructural heterogeneity. Corrosion tests demonstrated that the 1.35Sn alloy exhibited accelerated uniform corrosion compared to the 1.00Sn alloy under both conditions, with weight gains approximately 15 % and 40 % higher after 400 d and 1000 h, respectively. However, both alloys completely suppressed nodular corrosion, unlike the reference Zr-4 alloy. This is attributed to the Ni addition, as the resulting NiO exhibits high solubility in the ZrO₂ matrix and a compatible Pilling-Bedworth ratio, which mitigates oxidation-induced stress. X-ray photoelectron spectroscopy (XPS) analysis indicated increased SnO₂ formation in the oxide outer surface and higher degree of oxidation of Fe, Cr, and Ni in the high-Sn alloy, contributing to stress accumulation within the oxide film. Cross-sectional SEM observations revealed a significantly higher density of microcracks in the high-Sn alloy, particularly within the inner columnar grain region. A stress-dominated mechanism is proposed as an alternative to the classical anion-vacancy model, in which Sn-induced volumetric expansion, t-ZrO₂ to m-ZrO₂ phase transformation, and oxidation of SPPs act synergistically to promote microcracking, oxide degradation, and accelerated corrosion. These findings offer new insights into Sn-accelerated corrosion mechanisms and provide a foundation for the further development of Nb-free zirconium alloys with potential for use in demanding environments such as those anticipated in some small modular reactors (SMRs) designs.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113544"},"PeriodicalIF":7.4,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787253","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 : 2025-12-10DOI: 10.1016/j.corsci.2025.113546
Siyu Hu , Xin Zhong , Dong Fan , Xiao You , Du Hong , Liping Huang , Yaran Niu , Xuebin Zheng
Rare-earth disilicates (RE2Si2O7) environmental barrier coatings (EBCs) face the problem of insufficient resistance to high-temperature water vapor corrosion. In this study, a novel non-equimolar multiple-rare-earth disilicate, (Yb0.7Er0.1Tm0.1Ho0.1)2Si2O7 ((4RExi)2Si2O7), was developed to improve the corrosion resistance of RE2Si2O7. Bi-layer (4RExi)2Si2O7/Si and Yb2Si2O7/Si EBCs were prepared using atmospheric plasma spray (APS), and their corrosion behaviors under water vapor environment at 1400 °C were studied. The results show that (4RExi)2Si2O7 exhibits better corrosion resistance compared with Yb2Si2O7, which is attributed to the better structural stability and increased lattice distortion. Compared to the Yb2Si2O7/Si, the thermally grown oxide (TGO) layer thickness in the (4RExi)2Si2O7/Si system decreased by 23.8 %, and no significant interfacial crack was observed after 300 h of exposure. Molecular dynamics calculations further reveal that the oxygen diffusion coefficient in (4RExi)2Si2O7 is approximately 13.6 % lower than that in Yb2Si2O7. The enhanced corrosion resistance is therefore attributed to the improved structural stability and the suppressed oxygen-diffusion kinetics, providing an effective strategy for designing durable EBCs.
{"title":"Enhanced high-temperature water vapor corrosion resistance of RE2Si2O7 environmental barrier coatings via non-equimolar multi-rare-earth design","authors":"Siyu Hu , Xin Zhong , Dong Fan , Xiao You , Du Hong , Liping Huang , Yaran Niu , Xuebin Zheng","doi":"10.1016/j.corsci.2025.113546","DOIUrl":"10.1016/j.corsci.2025.113546","url":null,"abstract":"<div><div>Rare-earth disilicates (RE<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>) environmental barrier coatings (EBCs) face the problem of insufficient resistance to high-temperature water vapor corrosion. In this study, a novel non-equimolar multiple-rare-earth disilicate, (Yb<sub>0.7</sub>Er<sub>0.1</sub>Tm<sub>0.1</sub>Ho<sub>0.1</sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> ((4RE<sub><em>xi</em></sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>), was developed to improve the corrosion resistance of RE<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>. Bi-layer (4RE<sub><em>xi</em></sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>/Si and Yb<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>/Si EBCs were prepared using atmospheric plasma spray (APS), and their corrosion behaviors under water vapor environment at 1400 °C were studied. The results show that (4RE<sub><em>xi</em></sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> exhibits better corrosion resistance compared with Yb<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>, which is attributed to the better structural stability and increased lattice distortion. Compared to the Yb<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>/Si, the thermally grown oxide (TGO) layer thickness in the (4RE<sub><em>xi</em></sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>/Si system decreased by 23.8 %, and no significant interfacial crack was observed after 300 h of exposure. Molecular dynamics calculations further reveal that the oxygen diffusion coefficient in (4RE<sub><em>xi</em></sub>)<sub>2</sub>Si<sub>2</sub>O<sub>7</sub> is approximately 13.6 % lower than that in Yb<sub>2</sub>Si<sub>2</sub>O<sub>7</sub>. The enhanced corrosion resistance is therefore attributed to the improved structural stability and the suppressed oxygen-diffusion kinetics, providing an effective strategy for designing durable EBCs.</div></div>","PeriodicalId":290,"journal":{"name":"Corrosion Science","volume":"260 ","pages":"Article 113546"},"PeriodicalIF":7.4,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734290","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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