Investigation of Formation and Inhibition Mechanism of Cerium Conversion Films on Al 2024 Alloy

稀土学报(英文版), 2002, 20(6): 640-645.

1.State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China

2.State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China

3.State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China

4.State Key Laboratory for Physical Chemistry of Solid Surfaces, Department of Chemistry, Department of Materials Science and Engineering, Xiamen University, Xiamen 361005, China

基金项目: 国家自然科学基金(20127302)

Investigation of Formation and Inhibition Mechanism of Cerium Conversion Films on Al 2024 Alloy

Keywords： rare earths

To study the mechanism of formation and inhibition of Ce conversion films on Al 2024-T3 alloy, scanning microreference electrode technique (SMRE) is used to probe the potential map on Al 2024-T3 in CeCl3 solution, the localized corrosion of Al alloy decreases with immersion time and disappears finally, which results from the competition of Cl- aggression and Ce3+ inhibition on alloy surface. The results of X-ray photoelectron spectroscopy (XPS) indicate that the Ce conversion films consist of Al2O3, CeO2 and Ce2O3(Ce(OH)3), and CeO2/Ce2O3 ratio decreases with the immersion time. When a critical pH for Ce(OH)3 formation was reached, Ce(OH)3 will precipitate on the micro cathodic area on alloy surface. Consequently, H2O2, the product of the catholic reaction will oxidize a part of Ce(OH)3 to CeO2, which appears a better corrosion resistance for Al alloys.

参考文献

[1]	Hinton B R W;Arnott D R;Ryan N E .Cerium conversion coating for the corrosion protection of aluminum[J].Materials Forum,1986,9:162.
[2]	Mansfeld F;Kim L;Shih H .Surface modification of Al alloys and Al-based metal matrix composites by chemical passivation[J].Corrosion Science,1987,27:997.
[3]	Arnott D R;Hinton B R W;Ryan N E .Cationic-film-forming inhibitors for the protection of the AA7075 aluminum alloy against corrosion naqueous chloride solution[J].CORROSION,1989,45:12.
[4]	Hinton B R W .Corrosion inhibition with rare earth metal salts[J].Journal of Alloys and Compounds,1992,180:15.
[5]	Aldykiewicz AJ.;Davenport AJ.;Isaacs HS. .THE INVESTIGATION OF CERIUM AS A CATHODIC INHIBITOR FOR ALUMINUM-COPPER ALLOYS[J].Journal of the Electrochemical Society,1995(10):3342-3350.
[6]	Mansfeld F;Chen C;Brcslin C B et al.Sealing of anodized aluminum alloys with rare earth metal salt solutions[J].Journal of the Electrochemical Society,1998,145:2792.
[7]	Yu X W;Cao C N;Yao Z M .Corrosion behavior of rare earth metal conversion coatings on aluminum alloy LY12[J].Materials Science and Engineering A,2000,284:56.
[8]	Dabala M.;Buchberger A.;Calliari I.;Armelao L. .Cerium-based conversion layers on aluminum alloys[J].Applied Surface Science: A Journal Devoted to the Properties of Interfaces in Relation to the Synthesis and Behaviour of Materials,2001(3/4):312-322.
[9]	Lin C J;Luo J L;Zhuo X D et al.Scanning microelectrode studies of early pitting corrosion of 18/8 stainless steel[J].CORROSION,1998,54:265.
[10]	Shao M H;Fu Y;Hu R G .Localized corrosion study of Al 2024-T3 alloys[J].物理化学学报,2000,18:350.
[11]	Trzaskoma P P;McCaffErty E;Crowe C R .Corrosion behavior of Sic/Al metal matrix composites[J].Journal of the Electrochemical Society,1983,130:1804.
[12]	Burroughs P;Hammet H;Orchard A F.Statellite structure in the X-ray photoelectron spectra of some binary and mixed oxides of lanthanum and cerium[J].Journal of the Chemical Society Dalton Transactions,1976:1686.
[13]	Kotani A;Mizuta H;Parlebas J C .Theory of core photoemission spectra in CeO2[J].Solid State communications,1985,53:805.
[14]	Chastain J.Hardbook of X-ray Photoelectron Spectroscopy[M].Minneapolis:Perkin Elmer,1992
[15]	Bodkris J O'M;Khan U M.Surface Electrochemistry[M].New York: Plenum Press,1993
[16]	Bohm S.;Greef R. .Kinetic and Mechanistic Studies of Rare Earth-Rich Protective Film Formation Using In Situ Ellipsometry[J].Journal of the Electrochemical Society,2000(9):3286-3293.
[17]	POURBAIX M.Atlas of Electrochemical Equilibria in Aqueous Solution[M].New York: Pergamon Press,1966

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Investigation of Formation and Inhibition Mechanism of Cerium Conversion Films on Al 2024 Alloy

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