Heroes and highlights in the history of diffusion

• Main Authors: Mehrer, Helmut, Stolwijk, Nicolaas A.
• Other Authors: Universität Münster, Institut für Materialphysik
• Format: Article
• Language: English
• Published: Universitätsbibliothek Leipzig 2015
• Subjects: Diffusion; Transport; diffusion; transport; ddc:530
• Online Access: http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188591; http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-188591; http://www.qucosa.de/fileadmin/data/qucosa/documents/18859/diff_fund_11%282009%291.pdf

The science of diffusion had its beginnings in the nineteenth century, although the blacksmiths and metal artisans of antiquity already, used diffusion phenomena to make such objects as hardened iron swords and gilded bronze wares. Diffusion as a scientific discipline is based on several cornerstones. The most important ones are: (i) The continuum theory of diffusion originating from the work of the German physiologist Adolf Fick, who was inspired by elegant experiments on diffusion in gases and of salt in water performed by the Scotsman Thomas Graham. (ii) The Brownian motion, observed for the first time by the Scotish botanist Robert Brown, was interpreted decades later by the famous German-Jewish physicist Albert Einstein and almost at the same time by the Polish physicist Marian von Smoluchowski. Their theory related the mean square displacement of atoms to the diffusion coefficient. This provided the statistical cornerstone of diffusion and bridged the gap between mechanics and thermodynamics. The Einstein-Smoluchowski relation was verified in tedious experiments by the French Nobel laureate Jean Baptiste Perrin and his coworkers. (iii) Solid-state diffusion was first studied systematically on the example of gold in lead by the British metallurgist Roberts-Austen in 1896. Using a natural radioisotope of lead the Austro-Hungarian Georg von Hevesy and his coworkers performed for the first time studies of self-diffusion in liquid and solid lead around 1920. (iv) The atomistics of diffusion in materials had to wait for the birthday of solid-state physics, heralded by the experiments of the German Nobel laureate Max von Laue. Equally important was the perception of the Russian and German scientists Jakov Frenkel and Walter Schottky, reinforced by the experiments of the American metallurgist Ernest Kirkendall, that point defects play an important role for the properties of crystalline substances, most notably for those controlling diffusion and the many properties that stem from it. (v) The American physicist and twofold Nobel laureate John Bardeen was the first who pointed out the role of correlation in defect-mediated diffusion in solids, an aspect, which was treated in great detail by the American physicist John Manning. (vi) The first systematic studies of grain-boundary diffusion, a transport phenomenon of fundamental as well as technological importance, were initiated by the American materials scientist David Turnbull.