Characterization of NiB amorphous alloys with x‐ray photoelectron and secondary ion mass spectroscopy

Abstract

Amorphous Ni-B alloys with nominal compositions 30 at.% B and 50 at.% B were produced via electrodeposition on pure Ni polycrystalline substrates. The surfaces of the alloys were characterized with x-ray photoelectron spectroscopy (XPS) and dynamic secondary ion mass spectrometry (DSIMS). Information on the compositional variation with depth was acquired with XPS both non-destructively, in angle-resolved mode (ARXPS), and destructively with argon ion etching, as well as with DSIMS. Boron oxide dominates the outermost surface of the alloys. Its presence also in the bulk of the alloys is attributed to oxidation during processing, whereas the presence of hydrogen detected with SIMS is attributed to adsorption occurring during processing. The Auger parameter concept and information from the primary and secondary structure of the XPS spectrum were employed to probe the electronic changes occurring upon alloying. It is suggested that the main electronic changes occurring are hybridization of the Ni spd states with the B sp states and an apparent increase of the electron density around the Ni sites.

Probing the electronic structure of NiX, (X = B, S, P) catalysts with XPS

“…Features of the primary and secondary structures of the X-ray photoelectron spectrum are very useful in surface electronic structure investigations. In this work, we use binding energy (BE) shifts of core level electrons, Auger parameter (AP) variations and changes in shake up satellite energy and intensity in order to understand the electronic changes occurring upon alloying Ni with B, S and P. Results of the studies on Ni-B alloys have been published elsewhere; 5,6 therefore, in this paper they are used only for comparison and subsequent discussion purposes.…”

A Study of Anodically Grown Hydroxide Films on an Amorphous Ni[sub 78]Si[sub 8]B[sub 14] Alloy

“…The existence of Ni͑OH͒ 2 on the outermost surface of Ni 78 Si 8 B 14 polarized at OC is also in agreement with observations in previous studies on Ni-B electrodeposited alloys. 35 The satellite of the Ni 2p 3/2 peak seen in Fig. 6 is broader for the spectrum of NiOOH ͑0.5 V RHE ͒ compared to the Ni͑OH͒ 2 ͑0.4 V RHE ͒, presumably as an effect of the oxide presence in NiOOH.…”

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Hydrotreating activity of bulk NiB alloy in model reaction of hydrodenitrogenation of carbazole

“…Formation of the boron oxide insted of NiO is termodynamically favourable because the former has a free energy of formation ( G) of −801 KJ/mol O 2 , whereas the latter has a G value −426 KJ/mol O 2 [20]. Therefore the "fresh" catalysts is composed of highly dispersed B species in NiB alloy and amorphous states of both B 2 O 3 and B [17], which is also observed after heat treatment at 350 • C in hydrogen and after reaction of alone HDN-Figs.…”