title: The influence of gravity on the precise measurement of solute diffusion coefficients in dilute liquid metals and metalloids.
abstract: It is now well known that the diffusion coefficient (D) measured in a laboratory in low earth orbit (LEO) is less than the corresponding value measured in a terrestrial laboratory. However, all LEO laboratories are subject to transient accelerations (g-jitter) superimposed on the steady reduced gravity environment of the space platform. In measurements of the diffusion coefficients for dilute binary alloys of Pb-(Ag, Au,Sb), Sb-(Ga,In), Bi-(Ag,Au,Sb), Sn-(Au,Sb), Al-(Fe, Ni,Si), and In-Sb in which g-jitter was suppressed, it was found that D proportional to T (temperature) if g-jitter was suppressed, rather than D proportional to T(2) as observed by earlier workers with g-jitter present. Furthermore, when a forced g-jitter was applied to a diffusion couple, the value measured for D increased. The significance of these results is reviewed in the light of recent work in which ab initio molecular dynamics simulations predicted a D proportional to T relationship.
authors.affiliation: Department of Materials and Metallurgical Engineering, Queen's University, Kingston, Ontario, Canada. smithrw@post.queensu.ca
authors.forename: Reginald W
authors.initials: RW
authors.lastname: Smith
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Zhu
authors.forename: Mark C
authors.initials: MC
authors.lastname: Tunnicliffe
authors.forename: Timothy J N
authors.initials: TJ
authors.lastname: Smith
authors.forename: Lowell
authors.initials: L
authors.lastname: Misener
authors.forename: Josee
authors.initials: J
authors.lastname: Adamson