Determination of the Surface Composition of Binary Alloys by Auger Electron Spectroscopy


Book Description

Auger electron spectroscopy was exploited as a means of determining the surface phase diagram of Au--Ag and Au--Sn alloys. Polycrystalline Au--Ag alloy foils of a wide range of composition (atom fractions of 0.15 to 0.97) were cleaned. The intensities of the Auger emission from transitions at several energies were measured and normalized to those of pure Au and Ag. The surface monolayer compositions of the alloys were determined. The Auger data was consistent with enrichment of Ag in the surface monolayer. Ingots of Au--Sn with bulk composition between 50 and 99 at % Au were prepared. The bulk structure and composition of these complex alloys were characterized by electron microprobe, x-ray diffraction, x-ray fluorescence and optical microscopy. The samples were cleaned and equilibrated in ultra high vacuum and the intensities of the Auger emission from transitions at several energies were measured and normalized to those of pure Au and pure Sn. Using the intensity model, the normalized Auger intensity ratios were used to determine the surface monolayer composition. Enrichment of Sn was found in the surface monolayer for disordered zeta and .cap alpha. phase alloys. The highly ordered delta (50.0 at % Au) phase alloy was found to exhibit no surface segregation. The surfaces of two phase alloys (delta and zeta) were found to be describable by the lever rule. The results were interpreted in terms of the bulk structures, ordering properties, and driving force for segregation of the alloys. The effects of ion sputtering upon the surface of Au--Ag and Au--Sn alloys were also investigated.







Auger Electron Spectroscopy


Book Description

Treatise on Materials Science and Technology, Volume 30: Auger Electron Spectroscopy examines Auger electron spectroscopy and its various uses, emphasizing both theoretical and experimental studies. This book discusses the historical development of auger electron spectroscopy, studies of surface segregation kinetics by auger electron spectroscopy, and local electronic structure information in auger electron spectroscopy. The metallurgical applications of auger electron spectroscopy and auger photoelectron coincidence spectroscopy are also elaborated. Other topics include the measurement of surface segregation kinetics by Auger electron spectroscopy, tempered martensite embrittlement, embrittlement of nonferrous alloys, and analysis of particle-matrix interfaces. The high-resolution scanning Auger electron spectroscopy, corrosion and stress corrosion cracking, and APECS instrumentation are likewise covered in this publication. This volume is suitable for researchers and electrical engineering students conducting work on Auger electron spectroscopy.




Characterization of Metals and Alloys


Book Description

A better understanding of the microstructure of metals and alloys has led to great advances in the performance and useful applications of these, the oldest of mankind's engineered materials. This book in the Materials Characterizations series focuses on the particular molecular and atomistic properties of metals insofar as how they affect the different techniques for measuring and analyzing internal structure, surface structure, and chemical/physical properties. It provides a vital connection between commonly used characterization techniques like Scanning Electron Microscopy and how such can be used in the various ways that metals are processed, machined, and used. Review of relevant mechanical and chemical properties of metals and how they affect characterization techniques Characterization techniques used for melting and casting, machining, and metallic thin films processes Concise summaries of major characterization technologies for metals and alloys, including Auger Electron Spectroscopy, Energy-Dispersive X-Ray Spectroscopy, Neutron Activation Analysis, Scanning Electron Microscopy, and Transmission Electron Spectroscopy










Auger- and X-Ray Photoelectron Spectroscopy in Materials Science


Book Description

To anyone who is interested in surface chemical analysis of materials on the nanometer scale, this book is prepared to give appropriate information. Based on typical application examples in materials science, a concise approach to all aspects of quantitative analysis of surfaces and thin films with AES and XPS is provided. Starting from basic principles which are step by step developed into practically useful equations, extensive guidance is given to graduate students as well as to experienced researchers. Key chapters are those on quantitative surface analysis and on quantitative depth profiling, including recent developments in topics such as surface excitation parameter and backscattering correction factor. Basic relations are derived for emission and excitation angle dependencies in the analysis of bulk material and of fractional nano-layer structures, and for both smooth and rough surfaces. It is shown how to optimize the analytical strategy, signal-to-noise ratio, certainty and detection limit. Worked examples for quantification of alloys and of layer structures in practical cases (e.g. contamination, evaporation, segregation and oxidation) are used to critically review different approaches to quantification with respect to average matrix correction factors and matrix relative sensitivity factors. State-of-the-art issues in quantitative, destructive and non-destructive depth profiling are discussed with emphasis on sputter depth profiling and on angle resolved XPS and AES. Taking into account preferential sputtering and electron backscattering corrections, an introduction to the mixing-roughness-information depth (MRI) model and its extensions is presented.




Auger Electron Spectroscopy


Book Description

Auger electron spectroscopy is rapidly developing into the single most powerful analytical technique in basic and applied science.for investigating the chemical and structural properties of solids. Its ex plosive growth beginning in 1967 was triggered by the development of Auger analyzers capable of de tecting one atom layer of material in a fraction of a second. Continued growth was guaranteed firstly by the commercial availability of apparatus which combined the capabilities of scanning electron mi croscopy and ion-mill depth profiling with Auger analysis, and secondly by the increasing need to know the atomistics of many processes in fundamental research and engineering applications. The expanding use of Auger analysis was accompanied by an increase in the number of publications dealing with it. Because of the developing nature of Auger spectroscopy, the articles have appeared in many different sources covering diverse disciplines, so that it is extremely difficult to discover just what has or has not been subjected to Auger analysis. In this situation, a comprehensive bibliography is obviou-sly useful to those both inside and outside the field. For those in the field, this bibliography should be a wonderful time saver for locating certain references, in researching a particular topic, or when considering various aspects of instrumentation or data analysis. This bibliography not only provides the most complete listing of references pertinent to surface Auger analysis available today, but it is also a basis for extrapolating from past trends to future expectations.