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InFLUEncE OF SO_4^(2-) AnD cl-On THE cORROSIOn BEHAVIOR OF cOPPER TUBE In AIR-cOnDITIOnInG SYSTEM

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 92-96页

作者： c.S.Wu Z.Zhang F.H.cao J.Q.Zhang J.M.Wang c.n.cao Department of chemistry Yuquan CampusZhejiang University Hangzhou 310027ChinaDepartment of Chemistry Yuquan CampusZhejiang University Hangzhou 310027ChinaDepartment of Chemistry Yuquan CampusZhejiang University Hangzhou 310027ChinaDepartment of Chemistry Yuquan CampusZhejiang University Hangzhou 310027China State Key Laboratory for Corrosion and Protection of Metals Shenyang 110016 ChinaDepartment of ChemistryYuquan Campus Zhejiang University Hangzhou 310027ChinaDepartment of ChemistryYuquan Campus Zhejiang University Hangzhou 310027China State Key Laboratory for Corrosion and Protection of MetalsShenyang 110016 China

The influence of chloride or sulphur dioxide on the corrosion behavior of copper tube in the air-conditioning system was studied using scanning electron microscope (SEM), energy dispersion spectrometer (EDS) and cyclic polarization techniques. The results showed that the corrosion of copper tube are mainly caused by the SO42- and cl- ions in the circulating water, and the former is mainly responsible for the general corrosion of the copper tube whilst the latter for the pitting corrosion. The different influences of SG42- and cl- ions on the corrosion type of copper tube may be attributed to that the radius of SO42- ion is much larger than that of cl- ion. Meanwhile the results also indicated that SO42- inhibits the pitting corrosion caused by cl- and cl- inhibits the general corrosion initiated by SO42- due to their competitive adsorption on the copper matrix.

关键词： copper corrosion behavior influence SO42- ion cl- ion

ELEcTROcHEMIcAL FEATURES DURInG PITTInG cORROSIOn OF LY12 ALUMInUM ALLOY In DIFFEREnT nEUTRAL SOLUTIOnS

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 319-326页

作者： Y.L.cheng J.F.Li J.Q.Zhang c.n.cao F.H.cao Z.Zhanq Departmentofchemistry YuquanCampusZhejiangUniversityHangzhou310027.China StateKeyLaboratoryforcorrosionandProtectionofMetals InstituteofMetalResearch.TheChineseAcademyofSciencesShenyang110016ChinaManuscriptreceived10July2002 inrevisedform10October2002

The electrochemical features of commercial airfrarne material, Al alloy LY12, in 0.349mol/L neutral sodium chloride (nacl) and sodium sulfate (nazSO^) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiody-namic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the nyquist plots of LY12 at different immersion time displayed different features, indicating that the cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO42- solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in nacl solution are greater than that in na2SO4 solution.

关键词： LY12 aluminum alloy pitting corrosion electrochemical impedance spectroscopy potentiodynamic polarization pit- morphology

InITIAL ATMOSPHERIc cORROSIOn OF ZInc In THE PRESEncE OF nH_4cl

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Acta Metallurgica Sinica(English Letters) 2004年第2期17卷 161-165页

作者： Q.Qu c.W.Yan L.Li L.Zhang G.H.Liu c.n.cao Departmentofchemistry YunnanUniversityKunming650091China StakeKeyLaboratoryforcorrosionandProtection InstituteofMetalResearchTheChineseAcademy LaboratoryforconservationandUtilizationofBio-Resources YunnanUniversityKunming650091China

Influence of nH_4 cl on the initial atmospheric corrosion of zinc was investigated viaquartz crystal microbalance (QcM) in laboratory at 80%RH and 25℃. The resultsshow that nH_4 cl can accelerate the initial corrosion of zinc. Mass gain increase withthe exposure time, but mass gain in the later doesn't change obviously due to theformation of the insoluble simonkolleite on zinc surface in the presence of nH_4 *** transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) wasused to characterize the corrosion products. Zn_5cl_2(OH)_8·H_2O,(nH_4)_2Zncl_4 andZnO are the corrosion products on zinc. Brief discussion on the mechanisms of at-mospheric corrosion of zinc in the presence of nH_4 cl was introduced.

关键词： atmospheric corrosion zinc nH_4cl

STUDY THE InFLUEncE OF H_(3)BO_(3)On THE ZInc ELEcTROPLATInG USInG ELEcTROcHEMIcAL nOISE TEcHnIQUE

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 661-666页

作者： Z.Zhang c.S.Wu Q.Y.cai Y.L.cheng F.H.cao J.Q.Zhang c.n.cao Departmentofchemistry ZhejiangUniversityHangzhou310027China StateKeyLaboratoryforcorrosionandProtection InstituteofMetalResearchTheChineseAcademyofSciencesShenyang110016China

The influence of H3BO3 on the zinc electroplating was studied using electrochemical noise technique, cyclic voltammetry and steady-state polarization method. The results showed that, under the experimental conditions, the deposition of zinc followed the mechanism of two-dimensional nucleation and subsequent grain growth. The addition of H3BO3 into the electroplating solution prominently changes the nucleation and growth kinetics of zinc deposits, which is directly related to the features of electrocrystallization noise and the corresponding structure of the electrodeposits. The results also shown that the electrochemical noise (En) technique can give more information about the electrodeposits structure and electroplating mechanism than other normal electrochemical measurements can give, such as steady-state polarization method and cyclic voltammetry technique.

关键词： zinc electroplating electrochemical noise electrocrystallization

STUDY OF THE X70 PIPELInE STEEL cORRODInG In 3.0wt% nacl SOLUTIOn USInG ELEcTROcHEMIcAL IMPEDAncE SPEcTROScOPY TEcHnIQUE

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 907-911页

作者： L.J.Zhang Z.Zhang F.H.cao J.Q.Zhang J.M.Wang c.n.cao Departmentofchemistry ZhejiangUniversityHangzhou310027China Departmentofchemistry ZhejiangUniversityHangzhou310027China／／ StateKeyLaboratoryforCorrosionandProtectionofMetalsInstituteofMetalResearchTheChineseAcademyofSciencesSlaenyang110016China

The corrosion process of the X70 pipeline steel in 3.0wt% nacl solution were studied using polarization method, and the chronological characteristics during the entire polarization plot were investigated in detail using EIS technique. In the active region of X70 steel, such as 20mV potential bias applied on open circuit potential (OcP), the impedance spectra was comprised of three parts: a high-frequency capacitive loop, a middle-frequency capacitive loop and a low-frequency inductive component. When positive polarization potential increased, the capacitive loops at high and middle frequency range merged, and the inductive component at low frequency shrunk. At high positive polarization potential bias (500-800mV vs. OcP), the high-frequency capacitive loop and the low-frequency inductive loop exhibited as disheveled points due to the synergism of the inhomogeneity of the corroding material and the localized corrosion. The results were fitted utilizing the equivalent circuits to simulate the impedance spectra and to interpret the electrochemical features shown during the experiments.

关键词： X70 pipeline steel corrosion polarization EIS

ELEcTROcHEMIcAL nOISE FEATURES OF PURE ALUMInUM DURInG PITTInG cORROSIOn In nEUTRAL nacl SOLUTIOn

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Acta Metallurgica Sinica(English Letters) 2003年第1期16卷 20-30页

作者： F.H.cao Z.Zhang Y.L.cheng J.F.Li J.Q.Zhang J.M.Wang c.n.cao Department of chemistry Zhejiang UniversityHangzhou 310027China State Key Laboratory for corrosion and Protection of Metals Institute of Metal ResearchThe Chinese Academy of SciencesShenyang 110016China

Spontaneous electrochemical noise (En) can be a rich source of information concerning the processes simultaneously occurring at a corroding interface. Potential noise fluctuations during the free corrosion of pure aluminum in different concentration of neutral sodium chloride solution are investigated, and the breakdown and restoration of passive metal's film are studied using potentiodynamic scanning (PDS) measurements and electrochemical impedance spectroscopy (EIS) technique. Two capacitance loops are observed in the nyquist plots in two kinds of concentration, and the corrosion process is under activation control at first, then become diffusion control within the oxide film and corrosion products of (Al(OH)p-mcl-m) accumulated on the surface of the corroding electrode. It is suggested that the pitting corrosion is much easier to occur for pure aluminum in 7.0wt% than in 2.0wt% nacl solution, and the high concentration of chloride ion in solution inhibits the repassivation of a metastable pit. The corrosion rate deterministic step does not involve cl-.

关键词： pure aluminum pitting corrosion electrochemical noise electrochemical impedance spectroscopy potentiodynamic scanning

characteristics of mercury substituent inhibitor in alkaline manganese dioxide/zinc batteries

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Characteristics of mercury substituent inhibitor in alkaline...

THE SYnERGISTIc InHIBITIOn STUDIES OF SEVERAL AMInES AnD cHLORIDE IOn On IROn In THE AcIDIc PERcHLORIDE SOLUTIOnS

2016浙江省腐蚀与防护工程技术研讨会--汽车车辆及部件腐蚀与防护学术研讨会

作者： J.M.WAnG Y.D.QIAn J.Q.ZHAnG c.n.cao Department of chemistry Zhejiang University

1 Introduction Manganese dioxide/zinc btteries are the most widely used portable electochemical power *** cells cause serious environmental pollution due to the fact that mercury is used as an anode additive for inhibiting zinc corrosion and extending shelf life[1,2].The disposal of large quantity of used cells inevitably results in mercury *** far there have been two approaches to achieving inhibition of zinc corrosion under the mercury-free condition[3-7].One is to alter the properties of the zinc by alloying it with other elements,the other is to modify

关键词： alkaline medium battery inhibitors zinc corrosion

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 952-957页

作者： J.H.Dong 1) ,J.Y.chen 2,3) and. c.n.cao 1) 1) State Key Laboratory for corrosion and Protection of Metals, Institute of corrosion and Protection of Metals, The chinese Academy of Sciences, Shenyang 110015, china 2) The International center

The effect of chloride ion on the corrosion inhibition of iron caused by dencylamine(DA), dipentylamine(DDA) and dodecylamine(DPA) has been investigated by measuring the inhibitory coefficients for the anodic and cathodic processes at corrosion potential. It has been shown that the major synergistic inhibition effects between amines and chloride ions occur in the cathodic process, very weak in the anodic process. The anodic inhibition mechanism follows the competing adsorptive model, while the cathodic inhibition mechanism follows the cooperative adsorptive model.

关键词： synergistic inhibition organic amine chloride ion

Zeros of complete Symmetric Polynomials over Finite Fields

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Journal of Systems Science & complexity 2024年第4期37卷 1772-1788页

作者： cao Wei School of Mathematics and Statistics Minnan Normal UniversityZhangzhou 363000China

Wan and Zhang(2021) obtained a nontrivial lower bound for the number of zeros of complete symmetric polynomials over finite fields,and proposed a problem whether their bound can be *** this paper,the author improves Wan-Zhang's bound from three *** proposed results are based on the estimates related to the number of certain permutations and the value sets of non-permutation polynomials associated to the complete symmetric *** the author believes that there are still possibilities to improve the bounds and hence Wan-Zhang's bound.

关键词： complete symmetric polynomial finite field permutation polynomial value set