Localised coating failure of epoxy coated aluminium alloy 2024–T3 in 0.5M NaCl solutions: Comparison of conventional electrochemical techniques and microelectrochemical methods

Abstract

The formation of red blisters is an important mode of coating failure on epoxy coated aluminium alloy (AA) 2024–T3 exposed to chloride solutions. In order to achieve a better understanding of the mechanisms behind blister formation and growth and to understand the influence of the environment, impedance spectroscopy with and without microelectrodes was applied to the localised study of coating defects on AA 2024–T3. The results allowed features observed in regular impedance spectroscopy to be related to local phenomena and thereby allowed validation of the equivalent circuits used for data interpretation. In addition the electrochemical properties of smaller blisters and of uncorroded substrate areas could be determined separately on the same specimen. Such data are not accessible via regular electrochemical impedance spectroscopy experiments if a large blister is present. The data proved that the two semicircles observed at low frequencies in a regular impedance spectrum solely reflect the corrosion reactions taking place within the blister. Evidence for a strong local decrease in the coating resistance of the top of the blister was found. The coating resistance on areas not corroded appeared to decrease even after the end of the initial water uptake, although the impedance was still several orders of magnitude higher than on top of the coating blister. The passive dissolution rate on non-blistered substrate areas seemed to remain unaffected by the presence of the blister.

Get full access to this article

View all access options for this article.

References

ILEVBARE

G. O.

SCULLY

J. R.

YUAN

and KELLY

R. G.

: Corrosion 2000 56 227–242.

DIMITROV

MANN

J. A.

and SIERADZKI

: J. Electrochem. Soc., 1999 146 98–102.

BUCHHEIT

R. G.

GRANT

R. P.

HLAVA

P. F.

MCKENZIE

and ZANDER

G. L.

: J. Electrochem. Soc., 1997 144 2621–2628.

BUCHHEIT

R. G.

MARTINEZ

M. A.

and MONTES

L. P.

: J. Electrochem. Soc., 2000 147 119–124.

SUTER

and ALMLIE

R. C.

: in ‘Critical factors in localised corrosion III’, (ed. Kelly

R. G.

et al), PV 98–17118–129; 1999

Pennington

NJ, Electrochemical Society.

SCHMUTZ

and FRANKEL

G. S.

: J. Electrochem. Soc., 1998 145 2295–2306.

ILEVBARE

G. O.

JEFFCOATE

C. S.

and SCULLY

J. R.

: in ‘Passivity and localised corrosion’, (ed. Seo

et al), PV 99-27269–279; 1999

Pennington, NJ

Electrochemical Society.

CHEN

G. S.

GAO

and WEI

R. P.

: Corrosion 1996 52 8–15.

SCULLY

J. R.

KNIGHT

T. O.

BUCHHEIT

R. G.

and PEEBLES

D. E.

: Corros. ScL 1993 35 185–195.

10.

BUCHHEIT

R. G.

: J. Electrochem. Soc., 1995 142 3994–3996.

11.

BOCHLER

KERIMO

GUILLAUME

and SMYRL

W. H.

: J. Electrochem. Soc., 2000 147 3691–3699.

12.

ALODAN

M. A.

and SMYRL

W. H.

: J. Electrochem. Soc., 1997 144 L282 —L284.

13.

ALODAN

M. A.

and SMYRL

W. H.

: J. Electrochem. Soc., 1998 145 1571–1577.

14.

BUCHHEIT

R. G.

MONTEZ

L. P.

MARTINEZ

M. A.

MICHEAL

and HLAVA

P. F.

: J. Electrochem. Soc., 1999 146 4424–4428.

15.

GUILLAUMIN

and MANKOWSKI

: COPTOS. ScL 1999 41 421—438.

16.

ILEVBARE

G. O.

and SCULLY

J. R.

: J. Electrochem. Soc., 2001, 148 B196—B207.

17.

ILEVBARE

G. O.

and SCULLY

J. R.

: Corrosion 2001, 57 134–152.

18.

LEIDHEISER

: Corrosion 1982 38 374—383.

19.

STORFER

S. J.

and YUHAS

S. A.

: Mater. Perform., 1989 28 35–41.

20.

NGUYEN

HUBBARD

J. B.

and POMMERSHEIM

J. M.

: J. Coating TechnoL 1996 68 45–56.

21.

GOWERS

K. R.

and SCANTLEBURY

J. D.

: COPTOS. ScL 1983 23 935–942.

22.

GREENFIELD

and SCANTLEBURY

: J. COPTOS. ScL Eng., 2000 3 paper 5.

23.

REKNERS

and KALNINS

: Prog. Org. Coatings 2000 38 35–42.

24.

KOSEK

J. R.

DUPONT

J. N.

and MARDER

A. R.

: Corrosion 1995 51 861–871.

25.

MURRAY

J. N.

and HACK

H. P.

: Corrosion 1991 47 480–489.

26.

CHEN

C.-T.

and SKERRY

B. S.

: Corrosion 1991 47 598–611.

27.

WEIJDE

D. H. VAN DER

VAN WESTING

E. P. M.

and DE WIT

J. H. W.

: Electrochim. Acta 1996 41 1103–1107.

28.

LEIDHEISER

and KENDIG

M. W.

: Corrosion 1976 32 69–76.

29.

DICKIE

R. A.

and SMITH

A. G.

: Chemtech 1980, 1 31–35.

30.

LEIDHEISER

JR : Corrosion 1983 39 189—201.

31.

LENG

STRECKEL

HOFMANN

and STRATMANN

: COPTOS. Sci., 1999 41 599–620.

32.

LEIDHEISER

JR and WANG

: J. Coating Technol 1981 53 77–84.

33.

MACQUEEN

R. C.

MIRON

R. R.

and GRANATA

R. D.

: J. Coating TechnoL 1996 68 75–82.

34.

SEHGAL

FRANKEL

G. S.

ZOOFAN

and ROKHLIN

: J. Electrochem. Soc., 2000 147 140–148.

35.

XIA

AKIYAMA

FRANKEL

and MCCREERY

: J. Electrochem. Soc., 2000 147 2556–2562.

36.

MCGOVERN

W. R.

SCHMUTZ

BUCHHEIT

R. G.

and MCCREERY

R. L.

: J. Electrochem. Soc., 2000 147 4494–4501.

37.

DIMITROV

MANN

J. A.

VUKMIROVIC

and SIERADZKI

: J. Electrochem. Soc., 2000 147 3283–3285.

38.

MIERISCH

A. M.

YUAN

KELLY

R. G.

and TAYLOR

S. R.

: J. Electrochem. Soc., 1999 146 4449–4454.

39.

MIERISCH

A. M.

and TAYLOR

S. R.

: in ‘Electrically based microstructural characterization II’, (ed. Gerhardt

R. A.

et al), 35 — 42; 1998

Warrendale, PA

Materials Research Society.

40.

MIERISCH

A. M.

and TAYLOR

S. R.

: J. COITOS. ScL Eng., 1992 2 paper 30.

41.

BOHNI

SUTER

and SCHREYER

: Electrochim. Acta 1995 40 1361–1368.

42.

PARK

and BOHNI

: in ‘Critical factors in localised corrosion III’, (ed. Kelly

R. G.

et al), PV 98–17635–641; 1999

Pennington

NJ, Electrochemical Society.

43.

PERREN

R. A.

SUTER

T. A.

UGGOWITZER

P. J.

WEBER

MAGDOWSKI

BOHNI

and SPEIDEL

M. O.

: COITOS. Sci., 2001 43 707–726.

44.

HASSEL

A. W.

and SEO

: Electrochim. Acta 1999, 44 3769—3777.

45.

HASSEL

A. W.

and SEO

: in ‘Passivity and localised corrosion’, (ed. Seo

et al), PV 99–27337–346; 1999

Pennington

NJ, Electrochemical Society.

46.

MANSFELD

and TSAI

C. H.

: Corrosion 1991 47 958–963.

47.

MANSFELD

KENDIG

M. W.

and TSAI

: Corrosion 1982 38 478 —485.

48.

MURRAY:

in ‘Organic coatings for corrosion control’, (ed. Bierwagen

G. P.

), ACS Symposium Series 68910–22; 1998 Washington DC, American Chemical Society.

49.

GRANDLE

and TAYLOR:

S. R.

Corros. Scl 1994, 50, 792 — 803.

50.

Fleig and MAIER

: Electrochim. Acta 1996 41 1003–1009.

51.

VANYSEK

and BIRSS

V. I.

: Proc. 198th Meeting of the Electrochemical Society Phoenix, AZ, USA October 2000

Electrochemical Society

Abstract355.

52.

LEGGAT

R. B.

: ‘Adhesion of epoxy primer to hydrotalcite conversion coated AA 2024’

PhD Thesis

University of Virginia, VA, USA

2002.

53.

COLE

K. S.

and COLE

R. H.

: J. Chem. Phys., 1941, 9 341–351.

54.

JONSCHER

A. K.

: Nature 1974 250 191–193.

55.

VAN WESTING

E. P. M.

FERRARI

G. M.

and DE WIT

J. H. W.

: COPTOS. SW., 1993 34 1511–1530.

56.

KERNER

and PAJKOSSY

: Electrochim. Acta 2000 46 207 —211.

57.

MACDONALD

J. R.

and KM. BRACHNIAN. Rev. Mod Phys., 1956 28 393–422.

58.

RAISTRICK

I. D.

: in ‘Impedance spectroscopy — emphasizing solid materials and systems’, (ed. MacDonald

J. R.

), 27–83; 1987

New York, NY

John Wiley and Sons.

59.

DE LEVIE

: J. Electroanal Chem., 1990 281 1–21.

60.

POULAIN

PETITJEAN

J.-P.

DUMONT

and DUGNOILLE

: Electrochim. Acta 1996 41 1223–1231.

61.

VAN WESTING

E. P.M.

FERRARI

G. M.

and DEWIT

J. H. W.

: COPTOS. Sci., 1994 36 957–977.

62.

BRASHER

D. M.

and KINGSBURY

A. H.

: J. AppL Chem., 1954 4 62–72.

63.

HIRAYAMA

and HARUYAMA

: Corrosion 1991 47 952–958.

64.

SCHNEIDER

and KELLY

R. G.

: to be published.

65.

BESSONE

J. B.

SALINAS

D. R.

MAYER

C. E.

EBERT

and LORENZ

W. J.

: Electrochim. Acta 1992 37 2283–2290.

66.

BESSONE

J. B.

MAYER

JIITTNER

and LORENZ

W. J.

: Electrochim. Acta 1983 28 171–175.

67.

LORENZ

W. J.

and MANSFELD

: Corros. Scl 1981, 21 647–672.

68.

MACDONALD

D. D.

and MCKUBRE

M. C. H.

: in ‘Impedance spectroscopy — emphasizing solid materials and systems’, (ed. MacDonald

J. R.

), 260 — 316; 1987

New York, NY

John Wiley and Sons.