Tecnologia em Metalurgia, Materiais e Mineração
https://tecnologiammm.com.br/article/doi/10.4322/2176-1523.20202407
Tecnologia em Metalurgia, Materiais e Mineração
Artigo Original - Edição Especial “Tributo ao Prof. T. R. Strohaecker”

Characterization of anodized and bare 7075-T6 aluminum alloy treated with Zr-based conversion coating

Jéssica Salles Pinheiro, Claudia Trindade Oliveira, Gabriel Regio, Nicolle Goi, Jane Zoppas Ferreira

Downloads: 0
Views: 240

Abstract

AA7075-T6 is an aluminum alloy that has a high mechanical resistance; however, it shows corrosion vulnerability. A usual method to improve the corrosion resistance is anodization in acidic medium, which forms a thin barrier layer and a thicker porous oxide layer over the surface. This ultimate layer must be sealed to avoid electrolyte penetration. In the present work, a Zr-based conversion coating was investigated as a novel method of cold sealing and compared to the precipitation over bare AA7075-T6. The samples were characterized by Scan Electronic Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX) to elucidate the mechanism of reaction on both natural aluminum oxide and anodic oxide layer. The hydrophobicity properties were evaluated by contact angle measurements. The mechanism of deposition suggested for the coating over the anodic oxide was analogue to the one that takes place over the bare alloy: an initial attack by fluoride ions, local pH increase and Zr oxide precipitation. It was also possible to precipitate Zr oxide inside the pores. An increase of 125% on the contact angle was observed for the Zr coating over anodized surfaces, while the increase over the bare alloy was of 32%. Therefore, a robust coating system can be proposed involving the anodic layer and the nanometric Zr oxide.

Keywords

Aluminum alloy; Anodizing; Conversion coating; Hydrophobicity.

Referências

1 Starke EAA Jr, Staley JT. Application of modern aluminum alloys to aircraft. Progress in Aerospace Sciences. 1996;32(2-3):131-172. http://dx.doi.org/10.1016/0376-0421(95)00004-6.

2 Park JK, Ardell AJ. Microstructures of the commercial 7075 Al alloy in the T651 and T7 tempers. Metallurgical Transactions. A, Physical Metallurgy and Materials Science. 1983;14(10):1957-1965. http://dx.doi.org/10.1007/BF02662363.

3 Tian W, Li S, Wang B, Liu J, Yu M. Pitting corrosion of naturally aged AA 7075 aluminum alloys with bimodal grain size. Evaluation and Program Planning. 2016 [cited 2020 Nov 30];113:1-16. Available at: https://ac.els-cdn.com/S0010938X16307508/1-s2.0-S0010938X16307508-main.pdf?_tid=2468f932-c95d-11e7-9f71- 00000aacb35e&acdnat=1510678934_a604a31ccc80e1f04153e94c61eec176

4 Harlow DG, Wei RP, Wang MZ. Statistical analysis of constituent particles in 7075-T6 aluminum alloy. Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science. 2006;37(11):3367-3373. http://dx.doi.org/10.1007/BF02586171.

5 Pao PS, Feng CR, Gill SJ. Corrosion fatigue crack initiation in aluminum alloys 7075 and 7050. Corrosion. 2000;56(10):1022-1031. http://dx.doi.org/10.5006/1.3294379.

6 Zhao J, Xia L, Sehgal A, Lu D, McCreery RL, Frankel GS. Effects of chromate and chromate conversion coatings on corrosion of aluminum alloy 2024-T3. Surface and Coatings Technology. 2001;140(1):51-57. http://dx.doi.org/10.1016/S0257-8972(01)01003-9.

7 Santa Coloma P, Izagirre U, Belaustegi Y, Jorcin JBB, Cano FJJ, Lapeña N. Chromium-free conversion coatings based on inorganic salts (Zr/Ti/Mn/Mo) for aluminum alloys used in aircraft applications. Applied Surface Science. 2015;345:24-35. http://dx.doi.org/10.1016/j.apsusc.2015.02.179.

8 Golru SS, Attar MM, Ramezanzadeh B. Morphological analysis and corrosion performance of zirconium based conversion coating on the aluminum alloy 1050. Journal of Industrial and Engineering Chemistry. 2015;24:233-244. http://dx.doi.org/10.1016/j.jiec.2014.09.036.

9 García-Rubio M, De Lara MP, Ocón P, Diekhoff S, Beneke M, Lavía A, et al. Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films. Electrochimica Acta. 2009;54(21):4789-4800. http://dx.doi.org/10.1016/j.electacta.2009.03.083.

10 Arenas MA, Conde A, De Damborenea JJ. Effect of acid traces on hydrothermal sealing of anodising layers on 2024 aluminium alloy. Electrochimica Acta. 2010;55(28):8704-8708. http://dx.doi.org/10.1016/j.electacta.2010.07.089.

11 García-Rubio M, Ocón P, Curioni M, Thompson GE, Skeldon P, Lavía A, et al. Degradation of the corrosion resistance of anodic oxide films through immersion in the anodising electrolyte. Corrosion Science. 2010;52(7):2219-2227. http://dx.doi.org/10.1016/j.corsci.2010.03.004.

12 Gonzalez JA, Lopez V, Otero E, Bautista A, Lizarbe R, Barba C, et al. Overaging of sealed and unsealed aluminium oxide films. Corrosion Science. 1997;39(6):1109-1118. http://dx.doi.org/10.1016/S0010-938X(97)00019-X.

13 O’Sullivan JP, Wood GC. The morphology and mechanism of formation of porous anodic films on aluminium. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 1970 [cited 2020 Nov 30];317(1531):511-543. Available at: http://rspa.royalsocietypublishing.org/cgi/doi/10.1098/rspa.1970.0129

14 Diggle JW, Downie TC, Goulding CW. Anodic oxide films on aluminum. Chemical Reviews. 1969;69(3):365-405. http://dx.doi.org/10.1021/cr60259a005.

15 Hu N, Dong X, He X, Browning JF, Schaefer DW. Effect of sealing on the morphology of anodized aluminum oxide. Corrosion Science. 2015;97:17-24. http://dx.doi.org/10.1016/j.corsci.2015.03.021.

16     Mauricio O, Ramirez P, Donatus U, Queiroz FM, Olivier MG, Costa I, et al. EIS investigation of a Ce ‐ based posttreatment step on the corrosion behaviour of Alclad AA2024 anodized in TSA. Surface and Interface Analysis. 2019;51:1260-1275.

17 Wang R, Wang L, He C, Lu M, Sun L. Studies on the sealing processes of corrosion resistant coatings formed on 2024 aluminium alloy with tartaric-sulfuric anodizing. Surface and Coatings Technology. 2019;360:369-375. http://dx.doi.org/10.1016/j.surfcoat.2018.12.092.

18 Costenaro H, Lanzutti A, Paint Y, Fedrizzi L, Terada M, Melo HG, et al. Corrosion resistance of 2524 Al alloy anodized in tartaric-sulphuric acid at different voltages and protected with a TEOS-GPTMS hybrid sol-gel coating. Surface and Coatings Technology. 2017;324:438-450. http://dx.doi.org/10.1016/j.surfcoat.2017.05.090.

19 Guadagnin HC. Corrosion resistance study of AA2524 anodized in sulphuric-tartaric acid and sealed with hybrid coatings [thesis]. São Paulo: Universidade de São Paulo; 2017 [cited 2018 Dec 8]. Available at: http://www.teses.usp.br/teses/disponiveis/3/3137/tde-20072017-152947/

20 Terada M, Queiroz FM, Aguiar DBS, Ayusso VH, Costenaro H, Olivier M, et al. Corrosion resistance of tartaricsulfuric acid anodized AA2024-T3 sealed with Ce and protected with hybrid sol-gel coating. Surface and Coatings Technology. 2019;372:422-426. http://dx.doi.org/10.1016/j.surfcoat.2019.05.028.

21 Pinheiro JS, Regio G, Cardoso HRP, Oliveira CT, Ferreira JZ. Influence of concentration and ph of hexafluorozirconic acid on corrosion resistance of anodized AA7075-T6. Materials Research. 2019;22(Supplement 1):e20190048. http://dx.doi.org/10.1590/1980-5373-mr-2019-0048.

22 Yu S, Wang L, Wu C, Feng T, Cheng Y, Bu Z, et al. Studies on the corrosion performance of an effective and novel sealing anodic oxide coating. Journal of Alloys and Compounds. 2020;817:153257. http://dx.doi.org/10.1016/j.jallcom.2019.153257.

23 Saenz de Miera M, Curioni M, Skeldon P, Thompson GE. The behaviour of second phase particles during anodizing of aluminium alloys. Corrosion Science. 2010;52(7):2489-2497. http://dx.doi.org/10.1016/j.corsci.2010.03.029.

24 Ma Y, Zhou X, Thompson GE, Curioni M, Hashimoto T, Skeldon P, et al. Anodic film formation on AA 2099-T8 aluminum alloy in tartaric-sulfuric acid. Journal of the Electrochemical Society. 2011;158(2):C17. http://dx.doi.org/10.1149/1.3523262.

25 Huang Y-S, Shih T-S, Chou J-H. Electrochemical behavior of anodized AA7075-T73 alloys as affected by the matrix structure. Applied Surface Science. 2013;283:249-257. http://dx.doi.org/10.1016/j.apsusc.2013.06.094.

26 Ma Y, Zhou X, Thompson GE, Curioni M, Skeldon P, Zhang X, et al. Anodic film growth on Al-Li-Cu alloy AA2099-T8. Electrochimica Acta. 2012;80:148-159. http://dx.doi.org/10.1016/j.electacta.2012.06.126.

27 Ma Y, Wu H, Zhou X, Li K, Liao Y, Liang Z, et al. Corrosion behavior of anodized Al-Cu-Li alloy: the role of intermetallic particle-introduced film defects. Corrosion Science. 2019;158:108110. http://dx.doi.org/10.1016/j.corsci.2019.108110.

28 Capelossi VR, Poelman M, Recloux I, Hernandez RPB, Melo HG, Olivier MG. Corrosion protection of clad 2024 aluminum alloy anodized in tartaric-sulfuric acid bath and protected with hybrid sol-gel coating. Electrochimica Acta. 2014;124:69-79. http://dx.doi.org/10.1016/j.electacta.2013.09.004.

29 Runge JM. The metallurgy of anodizing aluminum. Cham: Springer International Publishing; 2018. http://dx.doi.org/10.1007/978-3-319-72177-4.

30 Hitzig J, Jüttner K, Lorenz WJJ, Paatsch W. AC-impedance measurements on porous aluminium oxide films. Corrosion Science. 1984;24(11-12):945-952. http://dx.doi.org/10.1016/0010-938X(84)90115-X.

31 Lunder O. Chromate-free pre-treatment of aluminium for adhesive bonding [thesis]. Trondheim: Fakultet for Naturvitenskap og Teknologi; 2003.

32 Andreatta F, Turco A, de Graeve I, Terryn H, de Wit JHW, Fedrizzi L. SKPFM and SEM study of the deposition mechanism of Zr/Ti based pre-treatment on AA6016 aluminum alloy. Surface and Coatings Technology. 2007;201(18):7668-7685. http://dx.doi.org/10.1016/j.surfcoat.2007.02.039.

33 Li L, Desouza AL, Swain GM. In situ pH measurement during the formation of conversion coatings on an aluminum alloy (AA2024). Analyst. 2013;138(15):4398-4402. http://dx.doi.org/10.1039/c3an00663h.

34 Li L, Whitman BW, Swain GM. Characterization and Performance of a Zr/Ti Pretreatment Conversion Coating on AA2024-T3. Journal of the Electrochemical Society. 2015;162(6):C279-C284. http://dx.doi.org/10.1149/2.0901506jes.

35 García-Rubio M, De Lara MP, Ocón P, Diekhoff S, Beneke M, Lavía A, et al. Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films. Electrochimica Acta. 2009;54(21):4789-4800. http://dx.doi.org/10.1016/j.electacta.2009.03.083.

36 Boisier G, Pébère N, Druez C, Villatte M, Suel S, Fesem SS, et al. FESEM and EIS study of sealed AA2024 T3 anodized in sulfuric acid electrolytes: influence of tartaric acid. Journal of the Electrochemical Society. 2008;155(11):521-529. http://dx.doi.org/10.1149/1.2969277.

37 Salles Pinheiro J, Zoppas Ferreira J. Proteção da liga AA7075-T6 por anodização tartárico-sulfúricae pós-tratamento comácido hexafluorozircônico [dissertation]. Porto Alegre: Universidade Federal do Rio Grande do Sul; 2019.

38 George FO, Skeldon P, Thompson GE. Formation of zirconium-based conversion coatings on aluminium and Al-Cu alloys. Corrosion Science. 2012;65:231-237. http://dx.doi.org/10.1016/j.corsci.2012.08.031.

39 Liu T, Dong L, Liu T, Yin Y. Investigations on reducing microbiologically-influenced corrosion of aluminum by using super-hydrophobic surfaces. Electrochimica Acta. 2010;55(18):5281-5285. http://dx.doi.org/10.1016/j.electacta.2010.04.082.

40 Thangavelu A, Sukumaran A, Hariprasad S, Gowtham S, Ravisankar B, Krishna LR, et al. Fabrication of corrosion resistant hydrophobic ceramic nanocomposite coatings on PEO treated AA7075. Ceramics International. 2018;44(1):874-884. http://dx.doi.org/10.1016/j.ceramint.2017.10.014.

41 Li Y, Li S, Zhang Y, Yu M, Liu J. Fabrication of superhydrophobic layered double hydroxides films with different metal cations on anodized aluminum 2198 alloy. Materials Letters. 2015;142:137-140. http://dx.doi.org/10.1016/j.matlet.2014.11.148.

42 Wenzel RN. Resistance of solid surfaces to wetting by water. Industrial & Engineering Chemistry. 1936;28(8):988-994. http://dx.doi.org/10.1021/ie50320a024.

43 Cassie BD, Baxter S. Wettability of porous surfaces. Transactions of the Faraday Society. 1944;40(5):546-551. http://dx.doi.org/10.1039/tf9444000546.

44 Verplanck N, Coffinier Y, Thomy V, Boukherroub R. Wettability switching techniques on superhydrophobic surfaces. Nanoscale Research Letters. 2007;2(12):577-596. http://dx.doi.org/10.1007/s11671-007-9102-4.

45 Niu JJ, Wang JN. A novel self-cleaning coating with silicon carbide nanowires. Washington: ACS Publications; 2020 [cited 2020 Nov 20]; Available at: https://pubs.acs.org/sharingguidelines


Submetido em:
30/06/2020

Aceito em:
04/12/2020

60704a14a953951b8109af53 tmm Articles
Links & Downloads

Tecnol. Metal. Mater. Min.

Share this page
Page Sections