Table of Contents
Textures and Microstructures
Volume 29 (1997), Issue 1-2, Pages 39-51

Calculation of the Effective Absorption Coefficient in Multi-Phase Powders

Philips Research Laboratories, Prof. Holstlaan 4, Eindhoven 5656 AA, The Netherlands

Received 14 February 1995

Copyright © 1997 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A calculation of the effective absorption coefficient μeff in multi-phase powders is presented. Characteristic in the calculation is, that the distribution function of the grains is similar to the correlation function for fluids. It is shown, that for average grain diameters comparable to the inverse of the absorption coefficients, the commonly used formulae for μeff (either a linear combination of the contituting μ's or simply μ for a single component) do not hold.

The analytical expressions derived for μeff are compared with numerical simulations, which show that, within certain limits, the former give reasonable estimates of μeff. The simulations also show, however, that shape effects can have influence on μeff which are not included (yet) in the formulae.

Also shown is that surface roughness can give effects comparable to those of microabsorption, but can be much more sensitive to particle statistics.