The effect of microstructure of nickel-aluminum bronze alloy (NAB) on the corrosion behavior in artificial seawater is studied using linear polarization, impedance and electrochemical noise tests. The alloy was heat treated in different heating cycles including quenching, normalizing and annealing. Microstructure of the specimens was characterized before and after heat treatment by optical microscopy and scanning electron microscopy. Results showed that the value of pearlite phase in the normalized alloy is much more than other specimens, leading to higher corrosion resistance. Polarization test showed that starting point of passivation in the polarization of the normalized alloy is lower than other specimens. The dissolution of Mn and Fe rich phases increased the Mn and Fe contents in solid solution, and this enhanced the passivation power of the surface of the alloy. The effect of the alloying elements was seen by a lower corrosion potential and an inflexion at around 280 mV (SCE) in the polarization curve, indicating the preferential dissolution of some elements beyond that potential. The polarization curve showed that the anodic polarization behavior of the alloy in the solution was essentially controlled by the intermetallic phases, mainly containing Cu. Two types of corrosion, pitting and selective corrosion, were observed in the specimens after being exposed to artificial seawater.
R. C. Barik, J. A. Wharton, R. J. K. Wood, K. S. Tan and K. R. Stokes, “Erosion and Erosion-Corrosion Performance of Cast and Thermally Sprayed Nickel-Aluminium Bronze,” Wear, Vol. 259, 2005, pp. 230-242. doi:10.1016/j.wear.2005.02.033
A. Al-Hashem and W. Riad, “The Role of Microstructure of Nickel-Aluminium-Bronze Alloy on its Cavitation Corrosion Behavior in Natural Seawater,” Materials Characterization, Vol. 48, 2002, pp. 37-41. doi:10.1016/S1044-5803(02)00196-1
F. Hasan, J. Iqbal and N. Ridley, “Microstructure of As- cast Aluminum Bronze Containing Iron,” Materials Science Technology, Vol. 1, 1985, p. 312.
F. Hasan, A. Jahanafrooz, G. W. Lorimer and N. Ridley, “The Morphology, Crystallography, and Chemistry of Phases in As-cast Nickel-Aluminum-Bronze,” Metallurgical Transactions A, Vol. 13A, 1982, p. 1337. doi:10.1007/BF02642870
J. A. Wharton, R. C. Brik, G. Kear, R. J. K. Wood, K. R. Stokes and F. C. Walsh, “The Corrosion of Nickel-Alu- minum Bronze in Seawater,” Corrosion Science, Vol. 47, 2005, pp. 3336-3367. doi:10.1016/j.corsci.2005.05.053
J. A. Wharton and K. R. Stokes, “The Influence of Nickel-Aluminum Bronze Microstructure and Crevice Solution on the Initiation of Crevice Corrosion,” Electrochimica Acta, Vol. 53, 2008, pp. 2463-2473. doi:10.1016/j.electacta.2007.10.047
M. D. Fuller, S. Swaminathan, A. P. Zhilyaev and T. R. Mcnelley, “Microstructural Transformations and Mechanical Properties of Cast NiAl Bronze: Effects of Fusion Welding and Friction Stir Processing,” Materials Science and Engineering A, Vol. 463, 2007, pp. 128-137. doi:10.1016/j.msea.2006.07.157
H. S. Campbell, “Aluminium Bronze Corrosion Resistance Guide,” Publication 80, Copper Development Association, UK, July 1981, pp. 1-27.
Z. Charlws and J. Ferrara Robert, “Sea Water Corrosion of Nickel-Aluminum Bronze,” Transactions of the American Foundrymen’s Society, Vol. 82, 1974, pp. 71-78.
R.-P. Chen, Z.-Q. Liang, W. W. Zhang, D.-T. Zhang, Z.-Q. Luo and Y.-Y. Li, “Effect of Heat Treatment on Microstructure and Properties of Hot-Extruded Nic- kel-Aluminum Bronze,” Transactions of Nonferrous Metals Society of China, Vol. 17, 2007, pp. 1254-1258. doi:10.1016/S1003-6326(07)60258-1
A. Schussler and H. E. Exner, “The Corrosion of Nickel-Aluminium Bronzes in Seawater-I. Protective Layer Formation and the Passivation Mechanism,” Corrosion Science, Vol. 34, 1993, p. 1793. doi:10.1016/0010-938X(93)90017-B
H. Meigh, “Cast and Wrought Aluminium Bronzes-Properties,” Processes and Structure, 1st Edition, IOM Communications, 2000.
F. L. LaQue, “Marine Corrosion,” Wiley, New York, 1975.
J. C. Rowlands, “Studies of the Preferential Phase Corrosion of Cast Nickel Aluminium Bronze in Seawater,” Proceeding of 8th International Congress of Metallic Corrosion, 1981, p. 1346.
G. Kear, B. D. Barker, K. R. Stokes and F. C. Walsh, “Electrochemical Corrosion of Unalloyed Copper in Chloride Media—A Critical Review,” Corrosion Science, Vol. 47, 2004, p. 1694. doi:10.1016/j.corsci.2004.08.013
G. Kear, B. D. Barker, K. R. Stokes and F. C. Walsh, “Electrochemical Corrosion Behaviour of 90-10Cu-Ni Alloy in Chloride-Based Electrolytes,” Journal of Applied Electrochemistry, Vol. 34, 2004, p. 659. doi:10.1023/B:JACH.0000031164.32520.58
G. Kear, B. D. Barker and F. C. Walsh, “Electrochemistry of Non-Aged 90-10 Copper-Nickel Alloy (UNS C70610) as a Function of Fluid Flow Part 1: Cathodic and Anodic Characteristics,” Electrochimica Acta, Vol. 52, No. 5, 2007, pp. 1889-1898. doi:10.1016/j.electacta.2006.07.054
K. Habib, “Measurement of the a.c. Impedance of Aluminum Samples by Holographic Interferometry,” Optics and Lasers in Engineering, Vol. 28, 1997, pp. 37-46. doi:10.1016/S0143-8166(96)00058-9
K. Habib, “Zero Resistance Ammeter of Metallic Alloys in Aqueous Solutions,” Optik-International Journal for Light and Electron Optics, Vol. 118, No. 6, 2007, pp. 296-301. doi:10.1016/j.ijleo.2006.03.023
B. Zhao, J.-H. Li, R.-G. Hu, R.-G. Du and C.-J. Lin, “Study on the Corrosion Behavior of Reinforcing Steel in Cement Mortar by Electrochemical Noise Measurements,” Electrochimica Acta, 2007, Vol. 52, pp. 3976-3984. doi:10.1016/j.electacta.2006.11.015
R. A. Cottis, “Interpretation of Electrochemical Noise Data,” NACE International Corrosion, Vol. 57, No. 3, 2009, pp. 65-23.
H.-H. Huang, W.-T. Tsai and J.-T. Lee, “The Influences of Microstructure and Composition on the Electrochemical Behavior of a516 Steel Weldment,” Corrosion Science, Vol. 36, No. 6, 1994, pp. 1027-1038. doi:10.1016/0010-938X(94)90201-1
F. T. Cheng, K. H. Lo and H. C. Man, “An Electrochemical Study of the Crevice Corrosion Resistance of NiTi in Hanks’ Solution,” Journal of Alloys and Compounds, Vol. 437, 2007, pp. 322-328. doi:10.1016/j.jallcom.2006.07.127
E. A. Culpan and R. Rose, “Corrosion Behaviour of Cast Nickel Aluminum Bronze in Sea Water,” British Corrosion Journal, Vol. 14, No. 3, 1979, p. 160.
G. W. Loriner, F. Hasan, J. Iqbal and N. Ridley, “Observation of Microstructure and Corrosion Behaviour of Some Aluminum Bronzes,” British Corrosion Journal, Vol. 21, 1986, No. 4, pp. 244-247.
A. Al-Hashem and W. Riad, “The Role of Microstructure of Nickel-Aluminium-Bronze Alloy on its Cavitation Corrosion Behavior in Natural Seawater,” Materials Characterization, Vol. 48, No. 1, 2002, pp. 37-41. doi:10.1016/S1044-5803(02)00196-1
H. Jafari, M. Hasbullah Idris, A. Ourdjini, H. Rahimi and B. Ghobadian, “EIS Study of Corrosion Behavior of Metallic Materials in Ethanol Blended Gasoline Containing Water as a Contaminant,” Fuel, Vol. 90, No. 3, 2011, pp. 1181-1187. doi:10.1016/j.fuel.2010.12.010
W. R. Osório, L. C. Peixoto, M. V. Canté and A. Garcia, “Electrochemical Corrosion Characterization of Al-Ni Alloys in a Dilute Sodium Chloride Solution,” Electrochim Acta, Vol. 55, No. 13, 2010, pp. 4078-4085. doi:10.1016/j.electacta.2010.02.029
W. R. Osório, L. C. Peixo, D. J. Moutinho, L. G. Gomes, I. L. Ferreira and A. Garcia, “Corrosion Resistance of Directionally Solidified Al-6Cu-1Si and Al-8Cu-3Si Alloys Castings,” Materials and Design, Vol. 32, No. 7, 2011, pp. 3832-3837.
W. R. Osório, L. C. Peixoto, M. V. Canté and A. Garcia, “Microstructure Features Affecting Mechanical Properties and Corrosion Behavior of a Hypoeutectic Al-Ni Alloy,” Materials and Design, Vol. 31, No. 9, 2010, pp. 4485-4489. doi:10.1016/j.matdes.2010.04.045
W. R. Osório, D. M. Rosa, L. C. Peixoto and A. Garcia, “Cell/Dendrite Transition and Electrochemical Corrosion of Pb-Sb Alloys for Lead-Acid Battery Applications,” Journal of Power Sources, Vol. 196, No. 15, 2011, pp. 6567-6572. doi:10.1016/j.jpowsour.2011.03.050