In Material Science

PIXE analysis method has been applied primarily for the nondestructive elemental analysis of ancient copper coins. However, the high 3uelds of the copper X-rays and the high background which is created, cause serious difficulties in the accurate determination of zinc, nickel, iron, and in general for the elements with medium and low atomic numbers (Katsanos et al. 1986). For this reason, the complementary methods of proton-induced prompt y-ray emission and proton activation methods have been explored. PIXE has been used in 

The use of nondispersive X-ray fluorescence spectroscopy has been well established as an anal3dical technique for many problems in alloy analysis and coating thickness measurements in basic metal industry, but the highest excitation efficiency is achieved when the entry of the exciting radiation is restricted to an energy, which is just above the absorption edge of the wanted elements. A characteristic line of the substrate material is chosen and its attenuation by the overlaying material helps to determine the thickness. For example, in a tin plated steel, it is possible to measure the ratio of FeKa from a coated and uncoated specimen in order to determine the thickness of tin. 

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Topics in Materials Science vol 7, ed E Kaldis (Amsterdam North-Holland) p 69... 

Biumioh B and Kuhn W (eds) 1992 Magnetic Resonance Microscopy Methods and Applications in Materials Science, Agriouiture and Biomedioine (Weinheim Wiiey-VCFI)... 

As a special development in recent years, SEMs have been designed which no longer necessitate high vacuum (enviromnental SEM, ESEM variable pressure SEM, VPSEM). This development is important for the imaging of samples with a residual vapour pressure, such as aqueous biological or medical samples, but also samples in materials science (wet rock) or organic chemistry (polymers). 

Light microscopy is of great importance for basic research, analysis in materials science and for the practical control of fabrication steps. Wlien used conventionally it serves to reveal structures of objects which are otherwise mvisible to the eye or magnifying glass, such as micrometre-sized structures of microelectronic devices on silicon wafers. The lateral resolution of the teclmique is detennined by the wavelength of tire light... 

Microscopes are also used as analytical tools for strain analysis in materials science, detenuination of refractive indices and for monitoring biological processes in vivo on a microscopic scale etc. In this case resolution is not necessarily the only important issue rather it is the sensitivity allowing the physical quantity under investigation to be accurately detennined. 

V Amelinck S, van Dyck D, van Landuyt J and van Trendelo G (eds) 1996 Handbook of Microscopy, Application In Materials Science, Solid State Physics and Chemistry 3 vols (Weinheim VCH)... 

Sawaoka A B (ed) 1993 Shock M/aves in Materials Science (New York Springer)... 

A challenging task in material science as well as in pharmaceutical research is to custom tailor a compound s properties. George S. Hammond stated that the most fundamental and lasting objective of synthesis is not production of new compounds, but production of properties (Norris Award Lecture, 1968). The molecular structure of an organic or inorganic compound determines its properties. Nevertheless, methods for the direct prediction of a compound s properties based on its molecular structure are usually not available (Figure 8-1). Therefore, the establishment of Quantitative Structure-Property Relationships (QSPRs) and Quantitative Structure-Activity Relationships (QSARs) uses an indirect approach in order to tackle this problem. In the first step, numerical descriptors encoding information about the molecular structure are calculated for a set of compounds. Secondly, statistical and artificial neural network models are used to predict the property or activity of interest based on these descriptors or a suitable subset. 

Cillan M J 1991. Calculating the Properties of Materials from Scratch, In Meyer M and V Pontikis (Editors). Computer Simulation, NATO ASI Series E 205 (Computer Simulations in Materials Science) pp. 257-281. 

Gale J D, C R A Catlow and W C Mackrodt 1992. Periodic Ab Initio Determination of Interatomic Potentials for Alumina. Modelling and Simulation in Materials Science and Engineering 1 73-81. 

D. J. Coimor, B. A. Sexton, and R. St. C. Smart, eds., Suface Analysis Methods in Materials Science, Springer Series in Suface Sciences, Vol. 23,... 

A. Rauber, in K. Kaldis, ed.. Current Topics in Materials Science Vol. 1, North Holland Publishing Co., Amsterdam, the Netherlands, 1978, p. 481. 

D. B. WiUiams, PracticaldinalyticalElectron Microscopy in Materials Science Electron Optics Publishing Group, Mahwah, N.J., 1987. 

M. S. DiesseUiaus and co-workeis. Graphite Fibers and Filaments Springer Series in Materials Science, Vol. 5, Springei-Vedag, New York, 1988. 

B. R. Lawn and R. J. Blau, eds.. Microindentation Techniques in Materials Science and Engineering, International Metakographic Society, ASTM STP 889, 1986. 

This kind of statistical consideration is used to detect oudiers, ie, when a sample does not belong to any known group. It is also the basis of a variation of SIMCA called asymmetric classification, where only one category is modelable and distinguished from all others, which spread randomly through hyperspace. This type of problem is commonly encountered in materials science, product quaUty, and stmcture—activity studies. 

K. C. Thompson-Russell and J. W. Edington. Electron Microscope Specimen Preparation Techniques in Materials Science. Monographs in Practical Electron Microscopy, No. 5- Philips Technical Library, Eindhoven Delaware, 1977. 

D. B. Williams. Practical Analytical Electron Microscopy in Materials Science. Verlag Chemie International, Weinheim, 1984. A good monograph discussing the use and applications of AEM, especially at intermediate voltages. The discussion on EDS is an excellent primer for using X-ray analysis on a TEM. 

L. H. Schwartz and J. B. Cohen. Diffraction from Materials. Springer-Verlag, Berlin, 1987. A recent text that includes X-ray, neutron, and electron diffiaction, but emphasizes XRD in materials science. A good introduction and highly recommended. 

As an example, we show in Figure 3 a backscattering spectrum from GaAs (110), obtained vwth a 300-keV Li ion beam. This is a well-chosen test example of energy resolution, as the atomic numbers of the two constituents are quite close (31 and 33 for Ga and As, respectively). Not only are these two species well resolved, but the two common isotopes of Ga are also well separated. Note that the peaks are asymmetric due to contributions from lower layers. Resolving power of this kind surely will find many new applications in materials science. 

Multilayer coatings of different composition and thickness are widely used in materials science and in the production of high-technology materials. The single- or multi-component thin layers significantly improve important characteristics of the materials with, e.g., specific properties. 

P. Rez in M. M. Disko, C. C. Ahn, B. Fultz (eds.) Transmission Electron Energy Loss Spectrometry in Materials Science, The Minerals, Metals and Materials Society, War-rendale 1992, p. 107. 

J. Heydenreich, W. Neumann (eds.) Proc. Analytical Transmission electron Microscopy in Materials Science - Fundamentals andTechni-ques, Elbe Druckerei, Wittenberg, 1993. 

Kelly, B.T., Nuclear reactor moderator materials. In Materials Science and Technology Nuclear Materials, Part 1 (VCH Weinheim, 1994) pp. 365-417. 

Cahn, R.W. (1992) Artifice and Artefacts 100 Essays in Materials Science (Institute of Physics Publishing, Bristol and Philadelphia) p. 314. 

Harwood, J.J. (1970) Emergence of the field and early hopes, in Materials Science and Engineering in the United States, ed. Roy, R. (Pennsylvania State University Press) p. 1. 

The sequence just outlined provides a salutary lesson in the nature of explanation in materials science. At first the process was a pure mystery. Then the relationship to the shape of the solid-solubility curve was uncovered that was a partial explanation. Next it was found that the microstructural process that leads to age-hardening involves a succession of intermediate phases, none of them in equilibrium (a very common situation in materials science as we now know). An understanding of how these intermediate phases interact with dislocations was a further stage in explanation. Then came an nnderstanding of the shape of the GP zones (planar in some alloys, globniar in others). Next, the kinetics of the hardening needed to be... 

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