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Temperature and NaCl deposition dependent corrosion of SAC305 solder alloy in simulated marine atmosphere

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Journal of Materials Science & Technology 2021年第16期75卷 252-264页

作者： Chuang Qiao Mingna Wang Long Hao Xiahe Liu Xiaolin Jiang Xizhong An Duanyang Li School of Metallurgy Northeastern UniversityShenyang110819China Environmental corrosion Centre of Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Department of Physics Hebei Normal University of Science technologyQinhuangdao066004China School of Material Science and Engineering University of Science and Technology of China.Hefei230026China College of Mechanical Engineering Institute of Innovative Science and TechnologyShenyang UniversityShenyang110044.China

The stable operation of electronic devices in marine atmospheric environment is affected by the corrosion deterioration of solder joints,and the effects by atmosphere temperature and chloride deposition are *** this work,NaCl deposition and temperature dependent corrosion of Pb-free SAC305 solder in simulated marine atmosphere has been *** results indicate that higher NaCl deposition prolongs the surface wetting time and leads to the final thicker saturated electrolyte film for further *** temperature accelerates the evaporation and contributes to the final thinner saturated NaCl electrolyte ***,the corrosion control process varies under the initially covered thicker NaCl electrolyte layer and under the final saturated much thinner NaCl electrolyte film as the evaporation ***,the ready oxygen availability through the final thinner saturated NaCl electrolyte film facilitates the formation of corrosion product layer mainly of electrochemically stable SnO2,but higher temperature leads to the final corrosion product layer with smaller crystal size and large *** findings clearly demonstrate the effects of NaCl deposition and temperature on corrosion evolution of SAC305 solder joints and are critical to the daily maintenance of electronic devices for longer service life in marine atmosphere.

关键词： atmospheric corrosion SAC305 solder Marine atmosphere NaCl Temperature

Advanced protection against environmental degradation of silver mirror stacks for space application

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Journal of Materials Science & Technology 2021年第5期64卷 1-9页

作者： Rajendra Kurapati Vincent Maurice Antoine Seyeux Lorena H.Klein Dimitri Mercier Gregory Chauveau Catherine Grees-Besset Loic Berthod Philippe Marcus PSL Research University CNRS-Chimie ParisTechInstitut De Recherche De Chimie ParisPhysical Chemistry of Surfaces Group11 Rue Pierre Et Marie Curie75005 ParisFrance CILAS MARSEILLE 600 Avenue De La Roche FourcadePole ALPHA Sud-Saint Mitre13400 AubagneFrance CNES Sous-direction Assurance QualitéService TechnologiesMatériaux Et Procédés18 AvenueÉdouard Belin31401 ToulouseFrance

Protection of silver mirror stacks from environmental degradation before launching is crucial for space ***,we report a comparative study of the advanced protection of silver mirror stacks for space telescopes provided by SiO_(2)and Al_(2)O_(3)coatings in conditions of accelerated aging by *** model silver stack samples were deposited by cathodic magnetron sputtering on a reference silica substrate for optical applications and a surface-pretreated SiC *** aging was per-formed in dry and more severe wet *** micrographic observations,surface and interface analysis by Time-of Flight Secondary Ion Mass Spectrometry(ToF-SIMS)and reflectivity measurements were combined to comparatively study the effects of *** results show a lower kinetics of degradation by accelerated aging of the stacks protected by the alumina coating in comparable test conditions.

关键词： Mirror layers Protection Layers Silver atmospheric corrosion Accelerated aging Surface analysis Space applications

corrosion behavior and corrosion products of a low-alloy weathering steel in Qingdao and Wanning

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 58-64页

作者： Shu-tao Wang Shan-wu Yang Ke-wei Gao Xin-lai He School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

A newly developed low-alloy weathering steel has been exposed in two coastal sites （Qingdao in the north, Wanning in the south） in China for one year. The samples in Wanning corroded far more seriously than those in Qingdao. The rust layer formed on the steel was analyzed by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, N2 adsorption approach, polarization curves, and electrochemical impedance spectroscopy （EIS）. The rust formed in Qingdao contains more X-ray amorphous compounds and is more compact than that formed in Wanning. Cr and Cu are enriched in the rust layer near the steel matrix, and the phenomenon is more obvious in Qingdao than in Wanning. The rust layer formed in Qingdao suppresses the anodic and cathodic reaction more remarkably than that formed in Wanning does. The rust layer formed in Qingdao possesses a higher ability to block the permeation of chloride ions than that formed in Wanning does.

关键词： low-alloy steel weathering steel atmospheric corrosion marine environment subtropical environment

Electrochemical Behaviour of Cu underneath Thin Electrolyte Film in Atmosphere

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Journal of Materials Science & Technology 1998年第6期14卷 547-550页

作者： Zhang, XY Du, YL Chinese Acad Sci Inst Corros & Protect Met State Key Lab Corros & Protect Shenyang 110015 Peoples R China

An electrochemical cell was devised to investigate corrosion electrochemical behavior of metal underneath thin electrolyte film in atmosphere. The Piontelli's type of Luggin-Haber capillary was inserted from the backward of working electrode. The results show that. cathodic process on Cu is mainly affected by the thickness of the electrolyte film of 0.5 mol/L HCl+1 mol/LNa2SO4 aqueous solution and its anodic dissolution changed from Tafel region to limiting diffusion current. Moreover, the corrosion potential of Cu in due media will increase with decrease of the thickness of the film.

关键词： atmospheric corrosion

Initial corrosion behaviors of AZ91 magnesium alloy in the presence of SO_2

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Journal of University of Science and Technology Beijing 2004年第5期11卷 433-441页

作者： CuiLin XiaogangLi corrosionandProtectionCenter KeyLaboratoryforCorrosionErosionandSurfaceTechnologyofBeijingUniversityofScienceandTechnologyBeijingBeijing100083China StateKeyLaboratoryforcorrosionandProtection InstituteofMetalResearchTheChineseAcademyofSciencesShenyang110016China

The effects of SO_2 on the initial atmospheric corrosion of AZ91D magnesiumalloy were investigated in laboratory. Met-allographic observation, SEM (Scanning ElectronMicroscopy), XRD (X-ray Diffraction) and XPS (X-ray Proton Spectrograph) were used to analyze anddiscuss the initial surface morphology of corrosion layers and corrosion products. The corrosionrate of the alloy increases with increasing the content of SO_2. The initial attack has thecharacteristics of localized corrosion and preferentially concentrates on a phase. MgO and Mg(OH)_2form at first, which provide a protective layer, then the existence of SO_2 decreases the pH of thethin solution on the alloy, accelerates dissolution process, and promotes the formation of MgSO_3centre dot 6H_2O and MgSO_4 centre dot 6H_2O, meanwhile cracks were found on the corrosion productswith corrosion continuation. These soluble corrosion products and the cracks provide the paths forfiltering oxygen and corrosion pollutants into the matrix, which results in severe localizedcorrosion and the loss of protective function of film.

关键词： AZ91D magnesium alloy SO_2 initial stages atmospheric corrosion

Incubation and development of corrosion in microstructures of low alloy steels under a thin liquid film of NaCl aqueous solution

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 748-755页

作者： Wen-hua Zhang Shan-wu Yang Jia Guo Zhi-yong Liu Xin-lai He School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Electrochemical measurement, optical microscopy, and scanning electron microscopy were employed to investigate the corrosion behavior of some low alloy steels. The steels were held under a thin liquid film of 0.5wt% NaCl aqueous solution. It is found that the steels with the same chemical composition but different micmstructures exhibit obviously different corrosion behaviors. However, the corrosion behavior of the steels with different compositions but the same microstructnres may be similar in the present investigation. The corrosion rate of bainite is slower than that of ferrite and pearlite. The corrosion products of bainite are uniform and fine. The size of carbon-rich phases produces a great impact on the corrosion of the steels, whether in the initial stage or in the long tenn. It is easy to induce large pitting for carbon-rich phases with large size, which damages the compactness of the rust layer.

关键词： alloy steel microstructure atmospheric corrosion liquid films scanning electron microscope

Effect of nickel on ion-selective property of rust formed on low-alloying weathering steel

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Acta Metallurgica Sinica(English Letters) 2012年第4期25卷 295-306页

作者： Xinliang GAO Guiqin FU Miaoyong ZHU School of Materials and Metallurgy Northeastern UniversityShenyang 110819China

The effect of nickel on the ion-selective property of the rust layers formed on the low alloy weathering steels under marine atmosphere was investigated by an alternate wet-dry accelerated corrosion test. Four types of low-alloying steels with different Ni contents were prepared for the corrosion test. The rust formed at various stages of corrosion was characterized by electrochemical impedance spectra （EIS）, electron microprobe analysis （EMPA） and scanning electron microscopy （SEM）. Afterwards, the corrosion resistance property of the rust was studied in the light of the exper- imental results. It is shown that increasing Ni content has significantly improved the corrosion resistance of the low-alloying steels under marine atmosphere. Further- more, it is noted that an evident cation-selective property emerges in the rust layers with the Ni content of the rust layers up to 1.82%. However, when the Ni content of steel the matrix is below 1.5%, it has little effect on the cation-selective property. The ratio of Ni content in between the rust layer and the steel substrate decreases with the increase of Ni content in the steel substrate and varies little as the corrosion proceeds.

关键词： atmospheric corrosion Nickel oxide EIS SEM

Quality control for bloom casting of YQ450NQR1 steel

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 32-36页

作者： Yong Chen Guo-rong Wu Miao-yong Zhu Materials and Metallurgy School Northeastern University Shenyang 110004 China Department of Material Research Panzhihua Iron and Steel Research Institute Panzhihua 617000 China

To reduce surface depression of a bloom, the primary cooling intensity was decreased, and the water distribution of mold wide and narrow faces was optimized. The length of secondary cooling zones and the specific water flow were increased, and the water flow distribution among the secondary cooling zones was adjusted to eliminate central defects, such as center looseness, central segregation, and center line cracks. The operation showed that the proportion of surface depression decreased from 37.22% to 2.87%, whereas the proportion of center looseness for 〈1.0 increased from 79.71% to 90.70%, the proportion of central segregation for 〈0.5 increased from 1.45% to 44.19%, and the proportion of center line cracks that are free increased from 39.13% to 62.79%. The qualified blooms are delivered to produce 310 Z-beam, whose yield strength is greater than 450 MPa.

关键词： corrosion resistant steel atmospheric corrosion bloom casting primary cooling secondary cooling quality control

Influence of Formic Acid on corrosion Behavior of Bronze under Thin Electrolyte Layer

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Journal of Wuhan University of Technology(Materials Science) 2022年第3期37卷 482-489页

作者： TANG Yijing CAI Lankun WANG Ying WANG Min ZHOU Hao WU Laiming YAN Ying School of Resources and Environmental Engineering East China University of Science and TechnologyShanghai 200237China Shanghai Museum Shanghai 200050China

The corrosion behavior of formic acid towards bronze under thin electrolyte layer(TEL)was investigated by means of electrochemical *** bronze had smaller self-corrosion current density than Cu_(2)O patina bronze and CuCl patina bronze,while it had higher polarization *** corrosion behavior of bronze materials had differences in various TELs and bulk *** critical thickness of TEL for Bare Bronze was 200μm,which normly occurred in the transformation from anode control to cathode *** thickness of TEL had a negligible effect on the corrosion rate of Cu_(2)O patina bronze when it was greater than 150μ*** CuCl patina bronze,the corrosion process accelerated with thinner *** was used to analyze the morphology and composition of corrosion ***_(2)O,Cu(OH)(HCOO)and Cu(HCOO)_(2)were formed on the surface of Bare Bronze and Cu_(2)O patina bronze,nevertheless,the main corrosion product of CuCl patina bronze was Cu_(2)Cl(OH)_(3).

关键词： EIS bronze formic acid atmospheric corrosion