IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Applied Surface Analysis Friday Sessions
       Session AS-FrM

Paper AS-FrM7
Auger Parameter Studies in Alloys of Transition Metals with Al or Mg

Friday, November 2, 2001, 10:20 am, Room 134

Session: Catalysis and Surface Reactivity
Presenter: M.-L. Abel, University of Surrey, UK
Authors: M.-L. Abel, University of Surrey, UK
P. Tsakiropoulos, University of Surrey, UK
J.F. Watts, University of Surrey, UK
J.A.D. Matthew, University of York, UK
Correspondent: Click to Email
Currently, alloys are designed either empirically or in a systematic and cost-effective way, which makes use of experimental and calculated phase equilibria (CALPHAD) data to select alloy composition with the desirable microstructures. The data obtained from this type of calculation are based on first principle calculations (FPC), but although phase diagrams predicted by FPC are topographically correct, they lack sufficient accuracy for practical applications. It is, therefore highly desirable to develop an experimental approach to the study of alloying behaviour. To produce alloys, a metallurgist usually considers the importance of such factors as the electronegativity difference or the atomic size mismatch in controlling the stability of metallic phases. The nature of alloying behaviour can be studied experimentally using the transfer of charge upon alloying. Quantification of charge transfer can be achieved using the Auger parameter and its variation over a wide composition range. This provides means of testing some of the predictions of FPC. In this work, transition metals have been selected because they form the basis of the constitution of conventional and development alloys. The aim of this research is to study hybridisation phenomena and the charge transfer between solvent and solute atoms in alloys. Changes of the Auger parameter determined from X-ray photoelectron experiments, is used as a tool to probe the electronic changes that take place as a result of alloying. The detection of the relevant Auger entries and core level energies is performed using the ESCA 300 in Daresbury (UK) which is fitted with a CrKb source. Core levels such as Si1s or Ti1s are then accessible and allow calculation of the Auger parameter of choice.