Insights into the characteristics of corrosion products formed on the contact and exposed regions of C1045 steel bolt and nut fasteners exposed to aqueous chloride environments  

作　　者：Enobong Felix Daniel Chao Li Changgang Wang Junhua Dong Inime Ime Udoh Peter Chukwuemeka Okafor Dongjiu Zhang Wenan Zhong Sheng Zhong 

机构地区：[1]School of Materials Science and Engineering,University of Science and Technology of China,Hefei 230026,China [2]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [3]School of Environmental and Chemical Engineering,Shenyang Ligong University,Shenyang 110159,China [4]Corrosion and Electrochemistry unit,Department of Pure and Applied Chemistry,University of Calabar,P.M.B 1115 Calabar,Cross River State,Nigeria [5]Key Laboratory of Space Launching Site Reliability,Xichang Satellite Launch Center,Hainan Haikou 571126,China

出　　处：《Journal of Materials Science & Technology》2023年第4期250-264,共15页材料科学技术（英文版）

基　　金：This work was financially supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2019193,KGFZD-135-19-02);the National Natural Science Foundation of China(No.51801219).Special appreciation to the CAS-TWAS Presidential Fellowship for sponsorship.

摘　　要：This study investigated the characteristics of corrosion products formed on the contact and exposed re-gions of C1045 steel bolt and nut fasteners exposed to aqueous chloride environments.The corroded sur-face morphology,rust compositions,and corrosion kinetics of the bolt specimen were studied by visual observation,optical microscopy(OM),scanning electron microscopy(SEM),X-Ray diffractometry(XRD),micro-Raman,electron probe micro-analyser(EPMA),and potentiodynamic polarization techniques.Re-sults obtained showed a variation in corrosion kinetics,morphology,and composition of the rust layer which were driven by differential aeration and concentration effects.Due to the availability of sufficient dissolved oxygen,the oxyhydroxide compound,lepidocrocite(γ-FeOOH)was detected in the outer rust layer in the exposed region,whereas the inner rust layer was composed of magnetite(Fe_(3)O_(4)).How-ever,the oxygen-deficient contact surface revealed the presence of akaganeite(β-FeOOH)and magnetite(Fe_(3)O_(4))as dominant oxide phases.The most stable phase,goethite(α-FeOOH)was also detected in the rust formed in both regions,though in significantly low amounts.Furthermore,owing to variation in environmental conditions,the amount and density of the rust layer varied in the different regions.The estimated corrosion stability values for the different regions revealed that the corrosion products formed on the steel surfaces were non-protective,suggesting the need for specific surface treatment as a protec-tive measure.

关 键 词：Carbon steel Bolt-nut fastener Raman SEM-EDS XRD Rust characterization 

分 类 号：TG172[金属学及工艺—金属表面处理]