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

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. Copyright (c) 2005 John Wiley & Sons, Ltd.