Galvanic corrosion behaviour of HE 20 / MDN 138 & HE 20 / MDN 250 alloys in natural seawater

Abstract

In view of their excellent mechanical properties, workability and heat treatment characteristics, MDN 138 & MDN 250 have been widely used in missile, rocket and aerospace industries. With light weight and high performance characteristics HE 20 aluminium alloy acts as an important material in defence and aerospace applications. The galvanic corrosion behaviour of the metal combinations HE 20 / MDN 138 and HE 20 / MDN 250, with 1:1 area ratio, has been studied in natural seawater using the open well facility of CECRI’s Offshore Platform at Tuticorin for a year. The open circuit potentials of MDN 138, MDN 250 and HE 20 of the individual metal, the mixed potential and galvanic current of the couples HE 20 / MDN 138 and HE 20 / MDN 250 were periodically monitored throughout the study period. The calcareous deposits on MDN 138 and MDN 250 were analysed using XRD. The results of the study reveal that that HE 20 has offered required amount of protection to MDN 138 & MDN 250.

Keywords

MDN 138 / MDN 250 / HE 20 / galvanic corrosion / natural seawater / aluminium alloy

References

[1] Little BJ, Wagner PA. The interrelationship between marine biofouling and cathodic protection, 1993

[2] Brooks RR, Presley BJ, Kaplan IR. APDC-MIBK extraction system for the determination of trace elements in saline waters by atomic absorption. Talanta, 1967, 14: 806-816

[3] Culberson CH. Effect of seawater chemistry on the formation of calcareous deposits, 1983

[4] Dexter SC, Lafontaine JP. Effect of natural marine biofilms of galvanic corrosion. Corrosion, 1989, 54: 851-861

[5] Dickinson WH, Caccavo F, Lewandowski Z. The ennoblement of stainless steel by manganic oxide biofilms. Corrosion Science, 1996, 38: 1407-1422

[6] Edyvean RGJ. Interactios between microfouling and the calcareous deposit formd on cathodically protected steel in seawater, 1987, 469-475

[7] Hack HP, Guanti RJ. Effect of high flow on calcareous deposits and cathodic protection current density. Mat Perf., 1989, 28: 29-35

[8] Hosni E, El-Houd A, El-Shawesh F. A study on the corrosion behavior of aluminum alloys in seawater. Materials and Design, 2008, 29: 801-805

[9] Jafarzadeh K, Shahrabi T, Hosseini MG. EIS study on pitting corrosion of AA5083-H321 aluminum-magnesium alloy in stagnant 3.5% NaCl solution. Journal of Materials Science and Technology -Shenyang, 2008, 24(2): 215-219

[10] Kunjapur M, Hartt W, Smith S. Influence of temperature on calcareous deposition cathodically polarized steel in seawater, 1985

[11] Lee R, Ambrose J. A hydrodynamical and chemical study of calcareous deposits, 1986

[12] Sarlak M, Shahrabi T, Zamanzade M. Investigation of calcareous deposits formation on copper and 316L stainless steel under cathodic polarization in artificial seawater. Protection of Metals and Physical Chemistry of Surfaces, 2009, 45(2): 216-222

[13] Strickland JDH, Parsons TR. A practical handbook of seawater analysis, 1972, Ottawa: Fisheries Research Board of Canada, 310

[14] Trdan AU, Grum J. Investigation of corrosion behaviour of aluminium alloy subjected to laser shock peening without a protective coating. Advances in Materials Science and Engineering, 2015, 2015: 1-9

[15] Wan Nik WB, Sulaiman O, Eng Giap SG, Rosliza R. Evaluation of inhibitive action of sodium benzoate on corrosion behaviour of AA6063 in seawater. International Journal of Technology, 2010, 1: 20-28

[16] Wan Nik WB, Sulaiman O, Ffadhli A, Rosliza R. Corrosion behaviour of aluminum alloy in seawater. Proceedings of MARTEC 2010, 2010, 175-180

[17] Wieng SM, Osvoll H, Gartland PO. Efficient cathodic protection to stainless steel small bore tubing, 2007