Magnesium corrosion behavior

Materials such as metals, alloys, steels and plastics form the theme of the fourth chapter. The behavior and use of cast irons, low alloy carbon steels and their application in atmospheric corrosion, fresh waters, seawater and soils are presented. This is followed by a discussion of stainless steels, martensitic steels and duplex steels and their behavior in various media. Aluminum and its alloys and their corrosion behavior in acids, fresh water, seawater, outdoor atmospheres and soils, copper and its alloys and their corrosion resistance in various media, nickel and its alloys and their corrosion behavior in various industrial environments, titanium and its alloys and their performance in various chemical environments, cobalt alloys and their applications, corrosion behavior of lead and its alloys, magnesium and its alloys together with their corrosion behavior, zinc and its alloys, along with their corrosion behavior, zirconium, its alloys and their corrosion behavior, tin and tin plate with their applications in atmospheric corrosion are discussed. The final part of the chapter concerns refractories and ceramics and polymeric materials and their application in various corrosive media. 

Zinc-manganese This alloy received attention when an US Air Force report was published [50]. In contact with metals more negative in the list of standard potentials than zinc, such as aluminum or magnesium, a better corrosion behavior is expected. Although the system found new interest in recent years [51,... 

G. Baril, C. Blanc, M. Kedam, N. Pebere, Local electrochemical impedance spectroscopy applied to the corrosion behavior of an AZ91 magnesium alloy, J. Electrochem. Soc. 150 (2003) B488-B493. 

S. Amira, M. Shehata, D. Dube, R. Tremblay, E. Ghalli, Corrosion behavior of die-cast and thixocast AXJ530 magnesium alloy in chloride medium, Adv. Mater. Res. 15—17 (2007) 449—454. 

It is well known that aluminum as such is fairly passive, because a very dense and uniform aluminum oxide AI2O3 layer is formed onto the metal to protect the metal from corrosion. Highly ductile light weight aluminum alloys that are passed through specific heat treatments can, however, make aluminum susceptible to corrosion. These materials may contain alloying elements such as magnesium and/or copper, which alter and complicate the corrosion behavior of aluminum. Typical forms of corrosion for the alloys are localized and pit corrosion. Due to the dense structure of the aluminum oxide layer, the corrosion rate of aluminum alloys is, however, substantially slower compared with corrosion/dissolution of CRS or HDG steel [15]. 

The major alloying elements are manganese, aluminium, zinc, zirconium, silicon, thorium, and rare earth metals (E). At present E elements are the most promising candidates for magnesium alloys, with high temperature stability as well as improved corrosion behavior. E metals are forming stable intermetallic compounds at high temperature and therefore they decrease casta-bility. Aluminium and zinc are introduced mainly to... 

Wu, G., Feng, K., Shanaghi, A., Zhao, Y., Xu, R., Yuan, G., Chu, P.K., 2012a. Effects of surface alloying on electrochemical corrosion behavior of oxygen-plasma-modified biomedical magnesium alloy. Surf. Coat. Technol. 206, 3186—3195. http //dx.doi.org/10.1016/ j.surfcoat.2012.01.001. 

Studies on stress-corrosion behavior of MMCs have been limited. Results for some aluminum and magnesium MMCs are summarized in the subsections on Effect of Reinforcement Constituents on Stress Corrosion in Al MMCs, and Effect of Alumirui in Magnesium MMCs respectively. The type of tests that can be used will depend to some degree on the form in which the MMC is produced emd whether or not the MMC can be precracked. Some types of MMCs are produced only in the form of relatively thin panels (e.g., less than about 0.25 cm), whereas other types are available in bars or tubes. It is sometimes impossible to proporiy precrack unidirectional, continuous-fiber MMCs because cracks do not always grow pjerpjendicular to the direction of applied stress [146]. 

This definition covers all the behavior of magnesium - start of the NDE behavior at a cathodic external current density, or at a potential negative to the magnesium corrosion potential. This new definition describes the main features of NDE. 

Zinc had a somewhat anomalous effect on the corrosion behavior of magnesium pro-... 

Yttrium (Unsworth and King, 1986 Joshi and Lewis, 1988 Krishnamurthyet al., 1988a Petrova and Krasnoyarskii, 1991 Miller etal., 1993), rare earth elements (Reichek et al., 1985 Krishnamurthy et al., 1988b Nisancioglu et al., 1990 Lunder et al., 1993), lithium (Petrova and Krasnoyarskii, 1987), silicon (Lunder et al., 1993 Hillis and Shook, 1989), lead (Petrova and Krasnoyarskii, 1988), calcium (Emley, 1966), and phosphorus (Chapter XX in Emley, 1966) also have some influence on the corrosion behavior of magnesium alloys. 

Microstructural properties such as grain size and phase distribution also play a role in determining corrosion behavior (Albright, 1988). Recent studies (Aune, 1983 Lunder et al., 1987) have found that fine, uniformly dispersed, cathodic phases were the most detrimental to the corrosion resistance of magnesium-based alloys (Albright, 1988). 

Albright, D. L. (1988), Relationship of microstructuFe and corrosion behavior in magnesium alloy ingots and castings, in Advances in Magnesium Alloys and Composites, Paris, H. G., Hunt, W. H. (Eds). International Magnesium Association and the Non-Ferrous Metals Committee, The Minerals, Metals, and Materials Society, Phoenix, Arizona, January 26, pp. 57-75. 

Aune, T. K. (1983), Minimizing base metal corrosion on magnesium products. The effect of element distribution (structure) on corrosion behavior, in Pmc. 40th World Magnesium Conference, Toronto, Ontario, Canada, June, 1983, McLean, VA International Magnesium Association. 

Lunder, O., Aune, T. K., Nisancioglu, K. (1985), The effect of Mn additions on the corrosion behavior of mold-cast magnesium alloy AZ91, NACE Corrosion 85 Conference, Paper 382, Boston, March 29, 1985. 

Chang, J.K., Chen, S.Y., Tsai, W.T. et al. (2007) Electrodeposition of aluminum on magnesium alloy in aluminum chloride (AlClj)- -ethyl-3-methylimidazolium chloride (EMIC) ionic liquid and its corrosion behavior. Electrvchem. Commun,9, 1602-1606. 

Nakatsugawa I. Kamado S., Kojima Y., Ninomiya R., Kubota K. (1996), Corrosion behavior of magnesium alloys containing heavy rare earth elements , in Lorimer G. W. (ed ), 3rd International Magnesium Conference, Manchester, pp 687-698. 

The atmospheric corrosion occurs frequently under thin electrolyte layers (TELs) or even adsorbed layers. The thickness of electrolyte has important role on corrosion phenomena such as the mass transport of dissolved oxygen, the accumulation of corrosion products, and the hydration of dissolved metal ions. The corrosion behavior of pure magnesium was investigated under aerated and de-aerated TELs with various thicknesses by means of cathodic polarization curve, electrochemical impedance spectroscopy (EIS) and EN measurements (Zhang et al, 2008). 

Andrei M, di Gabriele F, Bonora P L and Scantlebury D (2003), Corrosion behavior of magnesium sacrificial anodes in tap water . Materials and Corrosion, 54, 5-11. 

Song G and Atrens A (1998), Corrosion behavior of skin layer and interior of die cast AZ91D, Magnesium Alloys and their Application, Germany, Journal of Werkstoff-Informations gesellschaft, 415-419. 

Abstract This chapter discusses the effect of microstructure and rare earth (RE) elements on the corrosion of magnesium (Mg) alloy. Firstly, this chapter discusses the effect of P-phase and microcrystallization on the corrosion behavior of magnesium. Secondly, it describes the roles of RE elements on the corrosion behavior of Mg alloys. 

Eliezer D, Uzan P and Aghion E (2003), Effect of second phases on the corrosion behavior of magnesium alloys , Mater. Sci. Eorum 419-422, 857-866. 

Gao Y, Wang C, Yao M, Liu H, (2007), Corrosion behavior of laser melted AZ91HP magnesium alloy , Materials and Corrosion, 58, 463 466. 

J Chen, J Dong, J Wang, E Han, W Kev, Effect of magnesium hydride on the corrosion behavior of an AZ91 magnesium alloy in sodium chloride solution. Corrosion Science, 2008, 50, 3610-3614. 

W Liu, E Cao, L Chang, Z Zhang, J Zhang, Effect of rare earth element Ce and La on corrosion behavior of AM60 magnesium alloy. Corrosion Science, 2009, 51, 1334-1343. 

Y.F. Jian, L.F. Liu, C.Q. Zhai, Y.P. Zhu and W.J. Ding, Corrosion behavior of pulse-plated Zn-Ni alloy coatings on AZ91D magnesium alloy in alkaline solutions . Thin Solid Films, 484, (2005), 232-237. 

---