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Corrosion Behaviour of Carbon Steel Fasteners in Neutral Chloride Solution

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 563-576页

作者： Enobong Felix Daniel Junhua Dong Xiaofang Li Ini-Ibehe Nabuk Etim Inime Ime Udoh rongyao ma Lei Chen Changgang Wang Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of materials Science and Engineering Northeastern UniversityShenyang 110819China School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang 110159China Department of marine Biology Akwa Ibom State UniversityP.M.B 1167UyoNigeria

An experimental model for simulating the corrosion of carbon steel fasteners(bolt and nut) composed of a contact carbon steel electrode(CCSE) and an exposed bare carbon steel plate electrode(BCSE) was designed. The effect of coupling on the corrosion process of the galvanically coupled carbon steel electrode was evaluated and compared with the self-corrosion process observed independently at the exposed and contact regions. Results obtained indicated that at an equal area ratio and uncoupled conditions, the corrosion rate is accelerated in the surface directly exposed to bulk solution compared to the bolt surface in contact with the nut. A coupling current was recorded when the exposed surface(BCSE) was electrically connected with the contact surface(CCSE);with the CCSE acting as the anode thereby suppressing the corrosion process in the exposed surface. By implication, the galvanic coupling between CCSE and BCSE increased the corrosion rate of CCSE. The diff erence in oxygen supply was responsible for the coupling effect observed in the system as there was no decrease in the solution pH. Moreover, varying the cathode-to-anode area( S c/S a) ratio significantly influenced the corrosion current density as increased S c/S a ratio resulted in an accelerated galvanic corrosion process. The corroded surfaces and interfaces were analysed using stereomicroscopy and scanning electron microscopy. X-ray diff ractometry was adopted for corrosion product characterization. The results obtained showed supportive evidence of the corrosion behaviour in carbon steel fasteners.

关键词： Bolt and nut Galvanic current density Zero resistance ammetry(ZRA) Coupling potential Differential aeration cell Carbon steel fasteners

Effects of bentonite content on the corrosion evolution of low carbon steel in simulated geological disposal environment

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Journal of materials Science & Technology 2021年第7期66卷 46-56页

作者： Xin Weia Junhua Dong Nan Chen Amar Prasad Yadav Qiying Ren Jie Wei Changgang Wang rongyao ma Wei Ke Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Environmental Corrosion Centre of materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Central Department of Chemistry Tribhuvan UniversityKathmanduNepal

The effects of bentonite content on the corrosion behavior of low carbon steel in 5 mM NaHCO3+ 1 mM NaCl + 1 mM Na2SO4 solution were investigated by electrochemical measurements combined with X-ray diffraction(XRD) and scanning electron microscopy(SEM). In the initial immersion stage, the cathodic process of low carbon steel corrosion was dominated by the reduction of dissolved oxygen, while it transformed to the reduction of ferric corrosion products with the immersion time. The presence of bentonite colloids could suppress the cathodic reduction of oxygen due to their barrier effect on the diffusion of oxygen. However, the barrier performance of bentonite layer was gradually deteriorated due to the coagulation and separation of bentonite colloids caused by the charge neutralization of iron corrosion products dissolved from the steel substrate. More bentonite colloids could maintain the barrier effect for a long time before it was deteriorated by the accumulation of corrosion products. Conversely,it could lose the performance completely, and the corrosion behavior of low carbon steel reverted to the same as that in the blank solution.

关键词： Low carbon steel Bentonite Electrochemical measurements Corrosion products Corrosion evolution

Electrochemical noise analysis on the pit corrosion susceptibility of biodegradable AZ31 magnesium alloy in four types of simulated body solutions

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Journal of materials Science & Technology 2018年第10期34卷 1876-1884页

作者： changgang wang liping wu fang xue rongyao ma ini-ibehe nabuk etim xuehui hao junhua dong wei ke Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

magnesium alloys have been investigated as biodegradable implant materials since the last century. Non-uniform degradation caused by local corrosion limits their application, and no appropriate technology has been used in the research. In this study, electrochemical noise has been used to study the pit corrosion on magnesium alloy AZ31 in four types of simulated body solutions, and the data have been analyzed using wavelet analysis and stochastic theory. Combining these with the conventional polarization curves, mass loss tests and scanning electron microscopy, the electrochemical noise results implied that AZ31 alloy in normal saline has the fastest corrosion rate, a high pit initiation rate, and maximum pit growth probability. In Hanks＇ balanced salt solution and phosphate-buffered saline, AZ31 alloy has a high pit initiation rate and larger pit growth probability, while in simulated body fluid, AZ31 alloy has the slowest corrosion rate, lowest pit initiation rate and smallest pit growth probability.

关键词： Biodegradable magnesium alloy Electrochemical noise (EN) Pit corrosion susceptibilities Wavelet analysis Stochastic model

Effects of rare earth modifying inclusions on the pitting corrosion of 13Cr4Ni martensitic stainless steel

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Journal of materials Science & Technology 2021年第34期93卷 232-243页

作者： Changgang Wang rongyao ma Yangtao Zhou Yang Liu Enobong Felix Daniel Xiaofang Li Pei Wang Junhua Dong Wei Ke Shenyang National Laboratory for materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China Environmental Corrosion Centre of materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

In this study,the pitting corrosion behavior of 13Cr4Ni martensitic stainless steel(BASE)and that modified with rare earth(REM)in 0.1 mol/L Na Cl solution were *** such as automatic secondary electron microscope(ASPEX PSEM detector),scanning electron microscope(SEM),transmission electron microscope(TEM),scanning Kelvin probe force microscope(SKP),potentiodynamic and potentiostatic polarizations were *** results obtained indicate that BASE steel contains Al_(2)O_(3)/Mn S,Al_(2)O_(3) and Mn S inclusions,while REM steels contain(La,Ce,Cr,Fe)-O and(La,Ce,Cr,Fe)-O-S *** with BASE steel,REM steel is more susceptible to induce the metastable pitting nucleation and repassivation,whereas it restrains the transition from metastable pitting to stable *** 0.021%rare earth element to BASE steel can reduce the number and area of inclusions,while that of 0.058%can increase the number and enlarged the size of inclusions,which is also the reason that pitting corrosion resistance of 58 REM steel is slightly lower than that of 21 REM *** the process of pitting corrosion induced by Al_(2)O_(3)/Mn S inclusions,Mn S is preferentially anodic dissolved,and also the matrix contacted with Al_(2)O_(3) is subsequently anodic *** REM steels,anodic dissolution preferentially occurs at the boundary between inclusions and matrix,while(La,Ce,Cr,Fe)-O inclusions chemically dissolve in local acidic environment or are separated from steel *** chemically dissolved substance(La^(3+) and Ce^(3+))of(La,Ce,Cr,Fe)-O inclusions are concentrated in pitting pits,which inhibits its continuous growth.

关键词： 13Cr4Ni martensitic stainless steel Rare earth modifying inclusion Al_(2)O_(3)/MnS inclusion Metastable pitting corrosion Stable pitting corrosion

Short-circuit failure modes and mechanism investigation of 1200 V planar SiC MOSFETs

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Journal of Semiconductors 2024年第12期45卷 136-143页

作者： Yi Huang Qiurui Chen rongyao ma Kaifeng Tang Qi Wang Hongsheng Zhang Ji Ding Dandan Xu Sheng Gao Genquan Han School of Optoelectronic Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China China Resources Microelectronics(Chongqing)Limited Chongqing 400030China School of microelectronics Xidian UniversityXi'an 710126China

This paper presents a comprehensive analysis of the short-circuit failure mechanisms in commercial 1.2 kV planar sili-con carbide(SiC)metal–oxide–semiconductor field-effect transistors(MOSFETs)under 400 and 800 V bus voltage *** study compares two products with varying short-circuit tolerances,scrutinizing their external characteristics and intrinsic fac-tors that influence their short-circuit *** and numerical analyses reveal that at 400 V,the differential ther-mal expansion between the source metal and the dielectric leads to cracking,which in turn facilitates the infiltration of liquid metal and results in a gate–source short *** 800 V,the failure mechanism is markedly different,attributed to the ther-mal carrier effect leading to the degradation of the gate oxide,which impedes the device's capacity to switch off,thereby trig-gering thermal *** paper proposes strategies to augment the short-circuit robustness of SiC MOSFETs at both volt-age levels,with the objective of fortifying the device's resistance to such failures.

关键词： SiC MOSFETs short-circuit failure mode mechanical stresses cracks hot spot

Comparing a novel Catfish flow restoration device and the Solitaire stent retriever for thrombectomy revascularisation in emergent largevessel occlusion stroke:a prospective randomised controlled study

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Stroke & Vascular Neurology 2023年第6期8卷 435-443页

作者： Gang Luo Xiaoyan Yan Guodong Xiao Liping Wei Ya li kun Nai bi jiang rongyao ma Wenhuo Chen Chun Fang Zhiming Zhou Jieqing Wan Ya Peng Guilian Zhang Junfeng Zhao Li Li Haicheng Yuan Jin Wu Bing Li Fan Zhang Yuhong Cheng Feng Gao Zhongrong Miao Department of Intervention Interventional Neuroradiology CenterBeijing Tiantan HospitalCapital Medical UniversityBeijingChina Department of Intervention Interventional Neuroradiology CenterChina National Clinical Research Center for Neurological DiseasesBeijingChina Biostatistics Peking University Clinical Research InstituteBeijingChina Neurology The Second Affiliated Hospital of Suzhou UniversityJiangsuChina Department of Neurology Luoyang Central Hospital Affiliated to Zhengzhou UniversityLuoyangHenanChina Neurosurgery Hotan District People's HospitalHotanChina Neurology Nanshi Hospital of NanyangNanyangChina Neurology Zhangzhou Municipal Hospital of Fujian Province and Zhangzhou Affiliated Hospital of Fujian Medical UniversityZhangzhouFujianChina Department of Intervention Tongji Hospital Affiliated to Tongji UniversityShanghaiShanghaiChina Department of Intervention The First Affiliated Hospital of Wannan Medical CollegeWuhuAnhuiChina Department of Neurosurgery Shanghai Jiao Tong University School of Medicine Affiliated Renji HospitalShanghaiChina Department of Neurosurgery Changzhou No.1 People's HospitalChangzhouChina Neurology The Second Affiliated Hospital of Xi'an Jiaotong UniversityXi'anChina Neurology Siping Central People’s HospitalSipingChina Department of Intervention Xijing Hospital of Air Force Military Medical UniversityXi'anChina Neurology Qingdao Central Medical GroupQingdaoChina Neurology The Second Affiliated Hospital of Nanjing Medical UniversityNanjingChina Department of Intervention Qindao University Medical College Affiliated Yantai Yuhuangding HospitalYantaiShandongChina Neurology Hainan General Hospital/Hainan Affiliated Hospital of Hainan Medical UniversityHainanChina Department of Intervention Linfen Central HospitalLinfenShanxiChina

Background The Catfish stent retriever is a newly developed mechanical thrombectomy device for rapid recanalisation in emergent large vessel occlusion(ELVO)*** current trial aimed to assess whether the Catfish stent retriever is non-inferior to the Solitaire stent retriever in terms of outcomes in ELVO *** This was a randomised,prospective,parallel-group,multicentre,open-label,non-inferiority study conducted at 18 sites in *** primary outcome was the proportion of cases with successful recanalisation(modified thrombolysis in cerebral infarction score of 2b or 3)following the *** efficacy outcomes included the National Institutes of Health Stroke Scale scores at 24 hours and 7 days or discharge if earlier,time from artery puncture to successful recanalisation and good clinical outcome(modified Rankin scale score≤2)at 90 *** outcomes included symptomatic intracranial haemorrhage,all cause-death and severe adverse events at 90 *** Between 3 march 2019 and 5 June 2021,118 and 120 patients were randomly allocated to the Catfish and Solitaire groups,*** primary endpoint after all endovascular procedures was non-inferior in the Catfish group(88.5%,100/113)than in the Solitaire group(87.7%,100/114),with a rate difference(RD)of 0.78%(95%CI-7.64 to-9.20;p=0.001).Sensitivity analysis only considering the per-protocol set also yielded similar results,with an RD of 0.83%(95%CI-7.03 to-8.70;p<0.001).Additionally,the proportions of cases with good clinical outcomes(47.8%vs 50.0%,p=0.739)and all-cause death rates(17.7%vs 18.8%,p=0.700)were similar in both groups at 90 *** The Catfish stent retriever is an effective and safe device for endovascular recanalisation in ELVO stroke..

关键词： Solitaire prospective throm

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静水压力对超纯Fe腐蚀行为的影响

金属学报 2019年第7期55卷 859-874页

作者：马荣耀王长罡穆鑫魏欣赵林董俊华柯伟中国科学院金属研究所沈阳110016 中国科学院大学北京100049

采用失重测试、动电位极化和电化学噪声研究了静水压力对超纯Fe在3.5%NaCl中腐蚀行为的影响。利用离散小波分析方法去除噪声信号的直流漂移,然后进行散粒噪声和随机分析;利用Hilbert-Huang变换对噪声信号进行时频分析;用SEM观察腐蚀试... 详细信息

采用失重测试、动电位极化和电化学噪声研究了静水压力对超纯Fe在3.5%NaCl中腐蚀行为的影响。利用离散小波分析方法去除噪声信号的直流漂移,然后进行散粒噪声和随机分析;利用Hilbert-Huang变换对噪声信号进行时频分析;用SEM观察腐蚀试样的表面形貌。失重测试和动电位极化的研究结果表明,增大静水压力提高了超纯Fe在3.5%NaCl中的腐蚀速率。电化学噪声分析结果表明,在整个浸泡期间,增大静水压力促进了点蚀的发展,提高了局部腐蚀的倾向。在浸泡初期,超纯Fe以发生局部腐蚀(如点蚀形核、亚稳态点蚀、点蚀)的模式为主,增大静水压力对点蚀形核过程有一定的抑制作用,降低了点蚀孕育速率,但对亚稳态点蚀和稳态点蚀的发展过程有促进作用,提高了点蚀生长概率;随着浸泡时间的延长,其逐渐转为以均匀腐蚀的模式为主,增大静水压力仍然促进亚稳态点蚀和稳态点蚀的发展,提高点蚀生长概率,但是却相对地抑制了均匀腐蚀过程。

关键词：静水压力电化学噪声散粒噪声理论随机分析 Hilbert-Huang变换

Corrosion Behaviour of Carbon Steel Fasteners in Neutral Chloride Solution

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Corrosion Behaviour of Carbon Steel Fasteners in Neutral Chl...

第十一届全国腐蚀与防护大会

作者： Enobong Felix Daniel Junhua Dong Xiaofang Li Ini-Ibehe Nabuk Etim Inime Ime Udoh ma rongyao Chen Lei Changgang Wang School of materials Science and Engineering University of Science and Technology of China Hefei Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

This report focuses on the galvanic-crevice effect in the corrosion behaviour of carbon steel bolt and nut fasteners in simulated marine environments. The experimental studies were conducted at both coupled and uncoupled conditions using electrochemical and weight loss methods. Surface analysis was performed via stereomicroscopy（SM） and scanning electron microscopy（SEM）. X-ray diffractometry（XRD） was adopted for corrosion products characterization. Results obtained indicate that at an equal area ratio, the corrosion rate is accelerated in the region directly exposed to bulk solution compared to the contact（crevice）region at uncoupled conditions. Under coupled conditions, the bolt-nut contact region acts as the anode thereby suppressing the corrosion process at the exposed region, resulting in an increased corrosion process at the contact region. The difference in oxygen supply is responsible for the galvanic-crevice effect observed in the system as there is no observable decrease in the solution pH. Moreover, varying the cathode-to-anode area（Sc/Sa） ratio significantly influences the corrosion current density as increased Sc/Sa ratio resulted in an accelerated galvanic corrosion process. This study provides useful insight into the formulation of effective corrosion control measures for carbon steel fasteners.

关键词： Bolt and nut galvanic current density ZRA coupling potential differential aeration cell

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静水压力对金属腐蚀热力学及动力学的影响

金属学报 2019年第2期55卷 281-290页

作者：马荣耀赵林王长罡穆鑫魏欣董俊华柯伟中国科学院金属研究所沈阳110016 中国科学院大学北京100049

以热力学和动力学为基础,分析了静水压力对电极反应中材料的活度、环境中离子的活度、气体的溶解度、活度或逸度的影响,讨论了静水压力对海水环境中的pH值及化学平衡的作用,给出了静水压力与电极反应平衡电极电位和交换电流密度的关系式... 详细信息

以热力学和动力学为基础,分析了静水压力对电极反应中材料的活度、环境中离子的活度、气体的溶解度、活度或逸度的影响,讨论了静水压力对海水环境中的pH值及化学平衡的作用,给出了静水压力与电极反应平衡电极电位和交换电流密度的关系式,并建立了静水压力影响活性金属腐蚀行为的理论模型。研究表明,静水压力可提高材料、环境中离子及溶解气体的活度,且这与其偏摩尔体积密切相关;静水压力对异相材料的活度差异具有放大效应,异相材料的偏摩尔体积相差越大,活度的差异越明显。升高静水压力可降低金属Fe和Al阳极溶解反应的平衡电极电位,同时降低其交换电流密度;升高静水压力可提高吸氧反应的平衡电极电位,降低其交换电流密度;升高静水压力可降低析氢反应的平衡电极电位,增大其交换电流密度。

关键词：静水压力活度逸度溶解度平衡电极电位交换电流密度