Local characterization of electrodeposited Ni–W amorphous alloys by Auger microanalysis M. Pisarek a,b , M. Janik-Czachor a, ⁎ , M. Donten c a Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland b Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warsaw, Poland c Faculty of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland Received 2 August 2006; accepted in revised form 20 August 2007 Available online 1 September 2007 Abstract Electrodeposited Ni–W alloy layers on a Cu substrate were examined with the aid of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), X-ray electron microanalysis, and local Auger microanalysis. The results confirmed a high degree of homogeneity among the alloy layers deposited in optimized electrochemical conditions. High resolution Scanning Auger Microscopy (SAM) and local Auger spectra suggest the formation of an “intelligent” interphase layer of Ni, deposited prior to Ni–W alloy deposition. This finding contributes to our knowledge of the physical chemistry of electrodeposited layer–substrate interaction and interfacial phenomena. © 2007 Elsevier B.V. All rights reserved. Keywords: Electrodeposition; Homogeneous Ni–W layer; Local SAM analysis; Auger microanalysis 1. Introduction Electrodeposited Ni–W and other tungsten-containing amor- phous alloys are of wide fundamental and practical interest as potential candidates for the electronics and magnetic storage devices industries and well as surface coatings. Therefore, they have been the subject of extensive discussion in the literature and studies in many scientific centers [1–8]. The introduction of W to alloys improves their durability, hardness and resistance to high temperatures. They are, unfortunately, not suitable as stainless steel coatings because of poor adherence and a tendency for residual stresses to appear, resulting in the formation of microcracks and consequent deterioration of the coatings. Donten et al. [9–13] suggested that these electro- deposited alloys may adhere well to Cu, apparently because of a similarity in the crystallographic structures of Cu and Ni. Indeed, nanocrystalline and amorphous Ni–W alloys, which were smooth in appearance, seemingly uniform, hard, and which adhered well to Cu, have been produced [5,9,12]. Chemically uniform coatings are of interest for practical applications as they are expected to be particularly resistant to corrosion, as indeed are chemically homogenous amorphous alloys of Fe [14], Al [15–17] or other amorphous metals [18]. Therefore, local analysis of coatings at nanoscale, at regions across the coating/substrate interface, may help in obtaining detailed information on the chemistry of these layers and, in turn, to optimize conditions facilitating homogeneity. A high resolution local characterization is necessary to gain an insight into the chemistry of those electrodeposited Ni–W alloys. The local chemical and morphological characteristics of the Ni–W alloys at the nanometer scale, in a cross-section of the alloy perpendicular to the adjacent substrate, should be monitored. Scanning Auger Microscopy (SAM) is a suitable technique for this purpose since it provides local chemical analysis. This technique offers information limited to a depth of 1 nm or less [19–22]. Simultaneously, lateral resolution of several nanometers can be obtained as shown on different heterogeneous systems [23–24]. The aim of this work was to perform a detailed morpholog- ical and local chemical characterization of Ni–W coatings, in cross-section, to estimate the degree of their homogeneity and to learn about the chemistry of the coating/substrate interphase. Available online at www.sciencedirect.com Surface & Coatings Technology 202 (2008) 1980 – 1984 www.elsevier.com/locate/surfcoat ⁎ Corresponding author. Tel.: +48 22 343 33 25; fax: +48 22 343 33 33. E-mail address: maria@ichf.edu.pl (M. Janik-Czachor). 0257-8972/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.surfcoat.2007.08.047