Article ID Journal Published Year Pages File Type
1470103 Corrosion Science 2010 6 Pages PDF
Abstract

Selective dissolution of Ni(γ) in a binary Ni(γ)/Ni3Al(γ′) two-phase alloy was performed in an aqueous electrolyte including 1 wt.% (NH4)2SO4 and 1 wt.% citric acid to obtain a rough, γ′-terminated surface. The electrochemical potential for the selective dissolution was determined from the polarization curves of the γ and γ′ single-phase alloys. The selective dissolution tests proved that γ was precisely removed above 1.7 VSCE, resulting in the formation of a rough, γ′-terminated surface. Surface analyses revealed that a passive AlOx, which retarded the dissolution, was preferentially formed on γ′, resulting in a successful selective dissolution.

Research highlights► Selective dissolution of γ in the γ/γ′ two-phase alloy is due to the difference in the dissolution rate between the γ and γ′ phases. ► Selective dissolution of γ in the γ/γ′ two-phase alloy is successfully achieved in the higher transpassive region above 1.7 VSCE, resulting in the formation of a rough, γ′-terminated surface. ► The passive AlOx is preferentially formed on the γ´ in the γ/γ′ two-phase alloy and retards the dissolution of the γ′ phase, resulting in the selective dissolution of γ.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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