Diffusivity and Mobility Data

Published

December 31, 2009

Author(s)

Carelyn E. Campbell

Abstract

Diffusion is the process by which molecules, atoms, ions, point defects, or other particle types migrate from a region of higher concentration to one of lower concentration. The diffusivity of an atom or diffusion coefficient is the rate at which a particle migrates through a particular material and is dependent on the temperature, composition gradient and pressure. Diffusivity determines how quickly equilibrium is reached from a non-equilibrium state. In solid state materials diffusion can occur by variety of different mechanisms. Lattice diffusion (bulk or volume diffusion) occurs as a result of individual jumps of atoms or point defects, such as vacancies, di-vacancies, or interstitials, within the crystal. Diffusion may also occur along the surface or line defects, such as grain boundaries or dislocations. These line, planar, and surface diffusion mechanisms are generally much faster than the lattice diffusion based-mechanisms and as a result are term high diffusivity paths (or short-circuit diffusivity). As much of the published diffusion data is for bulk diffusion processes and many of microstructure evolution and processing models rely on bulk diffusion coefficients, this chapter will primarily focus on the diffusivity data and modeling of lattice diffusion in solid-state materials

Citation

ASM Handbook

Volume

22

Publisher Info

ASM International, Materials Park, OH

Pub Type

Book Chapters

Download Paper

Local Download

Citation

Campbell, C. (2009), Diffusivity and Mobility Data, ASM Handbook, ASM International, Materials Park, OH, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=854444 (Accessed October 31, 2024)