Professor James Castle

The Auger parameter (AP) is a value extracted from the X‐ray photoelectron spectrum (XPS) by addition of the binding energy of a photoelectron, for a given element in the spectrum, to the kinetic energy of the Auger electron emitted as the resulting hole in the electronic structure is filled by an electron from one of the outer orbitals. The value of the AP is sensitive to the polarization of electrons in the orbitals of neighbouring ions towards the photo‐ionized atom and is thus related to other opto‐electronic properties of the material. A correlation had been shown between the refractive index and the AP of aluminosilicates and thus the ability to compare, on a single chart, the AP's of the Al and Si ions gave important structural information. This comparison was made possible by normalising the individual APs to a common zero‐point. In this contribution, the methodology employed is extended to a wider range of elements. The resulting ability, to compare and contrast the normalised AP, thus generated, greatly enhances the information available from XPS and thus relates it directly to the polarizability of the material's structure.

The very thin native oxide film on stainless steel, of the order of 2 nm, is known to be readily modified by immersion in aqueous media. In this paper, XPS and ToF-SIMS are employed to investigate the nature of the air-formed film and modification after water emmersion. The film is described in terms of oxide, hydroxide and water content. The preferential dissolution of iron is shown to occur on immersion. It is shown that a water absorbed layer and a hydroxide layer are present above the oxide-like passive film. The concentrations of water and hydroxide appear to be higher in the case of exposure to water. A secure method for the peak fitting of Fe2p and Cr2p XPS spectra of such films on their metallic substrates is described. The importance of XPS survey spectra is underlined and the feasibility of C60+ SIMS depth profiling of a thin oxide layer is shown.

This study investigates the formation of a chromate conversion coating at Al–Cu–Fe–Mn intermetallic sites of an Al2219 alloy and the corrosion initiation at these sites in a 3.5% NaCl solution, using SEM, AES and EDX. Changes in the surface chemistry were monitored after progressive exposures to the solution up to 42 h. The coating was found to be thinner and more defective on the intermetallic. Initially, Al is dissolved and Al(OH)3 deposited on and around the intermetallic. After 42 h of exposure, Al(OH)3, Fe and Mn oxides and small particles of elemental Cu are deposited as corrosion products.

Herein we report the construction of a Wagner chemical state plot for beryllium containing the: metallic, oxide, nitride and carbide forms of beryllium by combining electron beam induced AES and XPS data. AES and XPS values were collected from metallic beryllium mechanically abraded in vacuum, bulk and native beryllium oxide and homogeneous secondary-phase beryllium nitride and beryllium carbide inclusions. XPS data for beryllium nitride and carbide were obtained from the literature.

Four samples of well-defined silicon-germanium alloys were used as standards for calibration purposes to allow accurate quantification of silicon-germanium-on-insulator (SGOI) microelectronic devices using Auger electron spectroscopy. Narrow Si KLL and the Ge LMM, high resolution Si KL_2,3L_2,3 and Ge L_3M_4,5M_4,5 together with survey spectra were collected and are presented from each sample. A matrix effect was observed for silicon in germanium and calculated as 0.85 and 0.95 for the Ge77.5Si22.5 Ge52.4Si47.6 alloys respectively.

As received beryllium and beryllium oxide, purchased from Goodfellow, were analysed by x-ray photoelectron spectroscopy. Survey spectra, high resolution spectra of elemental peaks and beryllium Auger transitions were collected and are presented. The binding energy of metallic beryllium 1s peak and the beryllium oxide 1s peak were found to be 110.5 and 113.4 eV respectively. The kinetic energy of the main metal and oxide KVV Auger transitions were found to be 103.5 and 95.5 eV respectively.

Lithium scribed in vacuum and a particle of lithium oxide were analysed by AES and lithium metal exposed to atmosphere for

To investigate the role of intermetallic particles in the localised corrosion of AA7075-T6, three particles were monitored over 16 hours immersion in 3.5 wt.% KCl solution. These were examined using Auger electron spectroscopy, energy dispersive x-ray spectroscopy, scanning Kelvin probe force microscopy and focused ion beam-scanning electron microscopy. Despite similar Volta potential measurements, the corrosion microchemistry varied significantly with composition. A Al7Cu2Fe intermetallic resulted in trenching while a (Al,Cu)6(Fe,Cu) intermetallic showed crevice corrosion and sub-surface intergranular corrosion and a Al12Fe3Si intermetallic appeared to be galvanically inactive but showed crevice formation at the matrix interface and sub-surface intergranular corrosion.

As-received beryllium, beryllium scribed in vacuum and beryllium oxide were analysed by Auger Electron Spectroscopy. As-received beryllium was analysed at low and high take off angles. Spectra produced demonstrate the change in the KLL structure with increasing oxygen concentration. Survey spectra as well as high resolution Be KLL and O KLL transitions were collected and are presented.

Secondary phase particles of beryllium nitride and beryllium carbide in beryllium were analysed by Auger Electron Spectroscopy. Survey spectra as well as high resolution Be KLL, N KLL and C KLL transitions were collected and are presented. The primary beryllium KLL Auger transitions for the nitride and carbide were recorded at 96.7 and 100.4 eV respectively. The homogeneity and composition of the secondary phase particles was confirmed by energy dispersive x-ray spectroscopy.

In this work, the feasibility of XPS analysis using locally generated Al K α radiation has been demonstrated. Both photo and Auger-electron signals can be obtained from a single, sub-micrometre, particle, achieving the aim of chemical state identi fi cation by means of the Auger parameter. The results, demonstrated in t his work using copper particles on an aluminium substrate, suggest that the technique, with further development, will be valuable for those concerned with the health hazards of nano-particles in general.

As-received beryllium and beryllium oxide were analysed by X-ray photoelectron spectroscopy and Auger electron spectroscopy. Additionally, beryllium metal was scribed in vacuum and analysed by AES. Survey spectra together with high-resolution spectra were acquired in XPS and AES mode and are presented here. The binding energies of the beryllium and the beryllium oxide Be 1s peaks were found to be 110.5 and 113.4 eV respectively, as collected by XPS, and the kinetic energies of the primary metal and oxide KLL Auger transitions were found to be 103.0 and 93.6 eV respectively, as collected by AES. Three loss peaks are also observed at 87.1, 78.0 and 67.2 eV in the AES spectrum of beryllium oxide