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XPS, UPS and AES study of surface segregation and oxidation of nickel-ruthenium alloy: evidence for decrease in dissociation temperature of nickel oxide in the presence of ruthenium

Hegde, MS and Kumar, Sampath TS and Mallya, RM (1987) XPS, UPS and AES study of surface segregation and oxidation of nickel-ruthenium alloy: evidence for decrease in dissociation temperature of nickel oxide in the presence of ruthenium. In: Surface Science, 188 (1-2). pp. 255-66.

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Abstract

Our AES study on the Ni-4.9at%Ru alloy shows Ru segregation to the surface with an enthalpy of segregation of −4 kJ/mol. On exposing the alloy to oxygen at 300 K, XPS and UPS studies show two types of oxygen species, $O^{2−}$ (529.4 eV) and $O^{1−}$ (531.4 eV); formation of NiO is also clearly observed. On heating the oxidized alloy surface in vacuum at 700 K, desorption of oxygen occurs as seen from the decrease in the O(1s) and O(KLL) peaks as well as the O(2p) band which was further confirmed by a thermal desorption study. Such a behaviour is attributed to the decrease in the dissociation temperature of NiO in the presence of Ru via $O^{2−}→O^{1−}$ conversion.

Item Type: Journal Article
Additional Information: Copyright belongs to Elsevier Science Publishers B.V.
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited: 14 Mar 2008
Last Modified: 19 Sep 2010 04:43
URI: http://eprints.iisc.ernet.in/id/eprint/13253

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