Corrosion behavior of 300M in neutralcorrosion environments containing Na Clsimulated by totalimmersion（TI）,salt spraying（SS）and periodic immersion（PI）,was investigated by surface analysis techniques,corrosion w...Corrosion behavior of 300M in neutralcorrosion environments containing Na Clsimulated by totalimmersion（TI）,salt spraying（SS）and periodic immersion（PI）,was investigated by surface analysis techniques,corrosion weight-loss method,and electrochemicalmeasurements.In totalimmersion environment,rust on the steelconsisted of a porous outer rust layer with main constituent of γ-Fe OOH,and an inner rust layer of dense Fe_3O_4 film with network broad cracks.In salt spraying environment,outer rust with main composition of γ-Fe OOH/α-Fe OOH/Fe_3O_4 was compact,and inner rust showed dense Fe_3O_4 film.Rust formed by periodic immersion exhibited a compact outer rust layer with constituent of α-Fe OOH/γ-Fe OOH/Fe_3O_4 and an inner rust layer with composition of α-Fe OOH/α-Fe_2O_3;inner rust showed a ultra-dense film adherent to the steel.The corrosion rate showed a rule of vss（salt spraying）〉vti（totalimmersion）〉〉vpi（periodic immersion）in 0-240 h,and vss≈vti？vpiin 240-720 h.The rust formed by periodic immersion was dense and compact,with stable electrochemicalproperties,and had excellent protection on the steel.Humidity and oxygen concentration in allthe environments played major roles in rust formation.展开更多
This paper investigates the corrosion fatigue (CF) crack initiation behavior of 316L stainless steel in Hank's solution which simulates bodylike fluid. The CF experiments were conducted under the conditions of ele...This paper investigates the corrosion fatigue (CF) crack initiation behavior of 316L stainless steel in Hank's solution which simulates bodylike fluid. The CF experiments were conducted under the conditions of electrochemically accelerated, free immersion and pre-polarized pitting potential. The results showed that 316L stainless steel was susceptible to pitting corrosion in Hank's solution. Intergranular corrosion occurred obviously at the bottom of pits where the CF cracks initiated by the combined action of alternating stress and corrosive medium for the notch effect of stress concentrated in the grain boundaries.The CF crack propagation is both intergranular and transgranular.展开更多
The environment and structure of the tanks used in aquaculture vessels are remarkably different from those of ordinary ships,and the resulting problem of structural strength is related to breeding safety.In this study...The environment and structure of the tanks used in aquaculture vessels are remarkably different from those of ordinary ships,and the resulting problem of structural strength is related to breeding safety.In this study,a model of aquaculture tank corrosion was constructed by using the multiphysical field coupling analysis software COMSOL Multiphysics,and wave and sloshing loads were calculated on the basis of potential flow theory and computational fluid dynamics.The influence of different calculation methods for corrosion allowance and sloshing load on the structural responses of aquaculture tanks was analyzed.Through our calculations,we found that the corrosion of aquaculture tanks is different from that of ordinary ships.The corrosion allowance in Rules for the Classification of Sea-going Steel Ships is small,and the influence of the aquaculture environment on corrosion can be ignored.Compared with the method set in the relevant rules,our proposed coupling direct calculation method for the structural response calculation of aquaculture tanks can better combine the specific environment of aquaculture tanks and provide more accurate calculations.展开更多
Metal-based electromagnetic interference(EMI)shielding composites are essential for ensuring electromagnetic compatibility but are often compromised by susceptibility to corrosion,especially in harsh environments.Exis...Metal-based electromagnetic interference(EMI)shielding composites are essential for ensuring electromagnetic compatibility but are often compromised by susceptibility to corrosion,especially in harsh environments.Existing strategies to mitigate coupling corrosion typically involve physical barriers,which inevitably hinder conductivity.In this study,we introduce a novel interface doping approach to fabricate lightweight Graphite@PDA/Ag@Ag composites that simultaneously enhance EMI shielding and corrosion resistance.The PDA/Ag layer selectively regulates electrons with different migration directions and energies to migrate,increasing charge transfer resistance at Ag/graphite interfaces and ensuring conductivity through a tunneling effect.This design achieves an ultralow corrosion rate of 4.313×10–8µm/y(a billionth that of 316 L stainless steel)alongside superior EMI shielding effectiveness of 109 dB in the X-band at 1.5 mm thickness.Remarkably,the composite maintains over 90 dB shielding efficiency after 7 d in NaCl solutions across various pH levels.Furthermore,simulated corrosion under South China Sea conditions predicts a coating loss of less than 0.026µm over 7 years.This work presents a transformative approach to mitigating coupling corrosion in EMI shielding materials,offering a practical route to high-performance,corrosion-resistant composites without the need for a protective topcoat.展开更多
基金Funded by the National Natural Science Foundation of China(No.51171011)
文摘Corrosion behavior of 300M in neutralcorrosion environments containing Na Clsimulated by totalimmersion（TI）,salt spraying（SS）and periodic immersion（PI）,was investigated by surface analysis techniques,corrosion weight-loss method,and electrochemicalmeasurements.In totalimmersion environment,rust on the steelconsisted of a porous outer rust layer with main constituent of γ-Fe OOH,and an inner rust layer of dense Fe_3O_4 film with network broad cracks.In salt spraying environment,outer rust with main composition of γ-Fe OOH/α-Fe OOH/Fe_3O_4 was compact,and inner rust showed dense Fe_3O_4 film.Rust formed by periodic immersion exhibited a compact outer rust layer with constituent of α-Fe OOH/γ-Fe OOH/Fe_3O_4 and an inner rust layer with composition of α-Fe OOH/α-Fe_2O_3;inner rust showed a ultra-dense film adherent to the steel.The corrosion rate showed a rule of vss（salt spraying）〉vti（totalimmersion）〉〉vpi（periodic immersion）in 0-240 h,and vss≈vti？vpiin 240-720 h.The rust formed by periodic immersion was dense and compact,with stable electrochemicalproperties,and had excellent protection on the steel.Humidity and oxygen concentration in allthe environments played major roles in rust formation.
文摘This paper investigates the corrosion fatigue (CF) crack initiation behavior of 316L stainless steel in Hank's solution which simulates bodylike fluid. The CF experiments were conducted under the conditions of electrochemically accelerated, free immersion and pre-polarized pitting potential. The results showed that 316L stainless steel was susceptible to pitting corrosion in Hank's solution. Intergranular corrosion occurred obviously at the bottom of pits where the CF cracks initiated by the combined action of alternating stress and corrosive medium for the notch effect of stress concentrated in the grain boundaries.The CF crack propagation is both intergranular and transgranular.
基金financially supported by the National Natural Science Foundation of China(Grant No.52071110)Fundamental Research Funds for the Central Universities(Grant No.3072022QBZ0101).
文摘The environment and structure of the tanks used in aquaculture vessels are remarkably different from those of ordinary ships,and the resulting problem of structural strength is related to breeding safety.In this study,a model of aquaculture tank corrosion was constructed by using the multiphysical field coupling analysis software COMSOL Multiphysics,and wave and sloshing loads were calculated on the basis of potential flow theory and computational fluid dynamics.The influence of different calculation methods for corrosion allowance and sloshing load on the structural responses of aquaculture tanks was analyzed.Through our calculations,we found that the corrosion of aquaculture tanks is different from that of ordinary ships.The corrosion allowance in Rules for the Classification of Sea-going Steel Ships is small,and the influence of the aquaculture environment on corrosion can be ignored.Compared with the method set in the relevant rules,our proposed coupling direct calculation method for the structural response calculation of aquaculture tanks can better combine the specific environment of aquaculture tanks and provide more accurate calculations.
基金supported by the National Science and Technology Major Project(No.J2019-VI-0015-013)Innovative Talent Promotion Program-Youth Science and Technology Emerging Project(No.2021KJXX-101)+5 种基金Science Fund for Distinguished Young Scholars of Shannxi Province(No.2023-JC-JQ-35)Fundamental Research Project of National Defense(No.2021-JCJQ-ZD-046-00)Northwestern Polytechnical University College Student Innovation and Entrepreneurship Training Program(No.S202310699574)National Natural Science Foundation of China(No.52302367)“Fundamental Research Funds for the Central Universities”(No.G2023KY05101)Special thanks to Dr.Minghui Fang(School of Materials Science and Engineering,Northwestern Polytechnical Uni-versity)for illustration production.
文摘Metal-based electromagnetic interference(EMI)shielding composites are essential for ensuring electromagnetic compatibility but are often compromised by susceptibility to corrosion,especially in harsh environments.Existing strategies to mitigate coupling corrosion typically involve physical barriers,which inevitably hinder conductivity.In this study,we introduce a novel interface doping approach to fabricate lightweight Graphite@PDA/Ag@Ag composites that simultaneously enhance EMI shielding and corrosion resistance.The PDA/Ag layer selectively regulates electrons with different migration directions and energies to migrate,increasing charge transfer resistance at Ag/graphite interfaces and ensuring conductivity through a tunneling effect.This design achieves an ultralow corrosion rate of 4.313×10–8µm/y(a billionth that of 316 L stainless steel)alongside superior EMI shielding effectiveness of 109 dB in the X-band at 1.5 mm thickness.Remarkably,the composite maintains over 90 dB shielding efficiency after 7 d in NaCl solutions across various pH levels.Furthermore,simulated corrosion under South China Sea conditions predicts a coating loss of less than 0.026µm over 7 years.This work presents a transformative approach to mitigating coupling corrosion in EMI shielding materials,offering a practical route to high-performance,corrosion-resistant composites without the need for a protective topcoat.
