Role of Nanostructure in Electrochemical Corrosion and High Temperature Oxidation: A Review

Abstract

The extremely fine grain size of nanocrystalline (nc) metallic alloys results in significantly different mechanical, electrochemical and oxidation properties as compared to the coarse-grained alloys of the same composition. Although the synthesis and attractive mechanical properties of nanocrystalline materials have been investigated and reviewed in great depth, the high temperature oxidation and electrochemical corrosion of these materials has received limited attention. The difference in the active dissolution and passivation behavior of nc alloys as compared to their microcrystalline counterparts varies for each alloy system. However, a unified theory explaining these phenomena still eludes us. In this context, this article reviews the progress in the electrochemical corrosion behavior of different nanocrystalline alloys, and hence, develops a better understanding of the effect of grain size, composition, interfacial phenomena and selective dissolution on corrosion of nanocrystalline alloys. This review also presents the role of nanometric grain size and the associated increase in grain boundary diffusion on the high temperature oxidation of nc alloys. The attractive possibility of enhanced oxidation resistance at lower alloying additions as compared to the coarse-grained alloys has been discussed. Although the primary focus of the article is on ferrous alloy systems, however, the lead studies on the role of ultrafine grain size in oxidation/corrosion behavior of other alloys systems have also been reviewed.

Spontaneous reaction formation of Cr23C6 diffusion barrier layer between nanocrystalline MCrAlY coating and Ni-base superalloy at high temperature

“…The nanocrystalline NiCrAlYHfSi coating exhibited good oxidation resistance at 1000 °C, similar to many previous researches [7][8][9][10]. Fig.…”

“…Reactive elements (REs), such as Y, Si, and Hf, are considered vital for the performance of MCrAlY coatings, because REs is benefit not only to improving adhesion of the thermally grown oxide (TGO) scales but also to decreasing the growth rates of TGO [5,6]. Nanocrystalline microstructures have been found greatly enhancing the oxidation resistance of MCrAlY coatings, because the critical concentration of Al for maintaining the growth of an external protective α-Al2O3 scale is decreased and the adherence of TGO is greatly improved [7][8][9][10].…”

Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP

“…Corrosion properties are also important for structural application. The beneficial effect of grain size reduction to the nanoscale was first demonstrated for intergranular corrosion in electrodeposited nanocrystalline nickel thanks to the pioneering work of Rofagha et al [6], Kim et al [7,8], followed by Mahesh and Raman [9]. They observed a rather smooth surface with a smaller penetration rate at grain boundaries and thus considerable improvement in intergranular corrosion.…”

Investigation of the Stability of Nanostructures to Degradation

“…In this connection, the final result of the corrosion degradation directly depends on the kinetic features of the surface and electrochemical reactions, the physical-chemical properties of nanomaterials as well as the method of their production and modification [9][10][11][12][13]. Moreover, the nature of the corrosion degradation of nanostructured materials is non-trivial, as evidenced by the contradictory data from various studies [14][15][16][17]. Copper oxide CuO nanostructured materials have drawn great interest of several research groups due their promissing applications in electrocatalysis and microelectronics [18][19].…”