Interdiffusion in the Ta‐W system
作者:
A. D. Romig,
M. J. Cieslak,
期刊:
Journal of Applied Physics
(AIP Available online 1985)
卷期:
Volume 58,
issue 9
页码: 3425-3429
ISSN:0021-8979
年代: 1985
DOI:10.1063/1.335761
出版商: AIP
数据来源: AIP
摘要:
Interdiffusion in the Ta‐W system, a continuous body‐centered‐cubic solid solution, has been investigated in the temperature range 1300–2100 °C with single‐phase diffusion couples prepared by chemical vapor deposition. Fine inclusions, presumably oxides or carbides, decorated the couple interfaces and served as Kirkendall markers. The diffusion annealing times ranged from 16 h to 220 days. The resulting concentration profiles were measured with the electron microprobe and analytical electron microscope. The chemical diffusion coefficient was determined by the classical Boltzmann–Matano technique. The intrinsic diffusivities were determined by the technique of Darken. In the composition range 20–80 at. % W, the activation energyQfor chemical diffusion was constant at 130.5±1.5 kcal/mole. The activation energies for the intrinsic diffusion coefficients at the composition of the Kirkendall marker plane, approximately 70 at. % W, wereQ(Ta)=132.3±0.5 kcal/mole andQ(W)=122.0±0.5 kcal/mole.
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