Time-dependent diffusion coefficients obtained from diffused films: The CuNi system
| Autor: | G. Subbaraman, C.R. Houska, F. Dietrich |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Reverse diffusion
Molecular diffusion Materials science Condensed matter physics Metals and Alloys Lattice diffusion coefficient Surfaces and Interfaces Surfaces Coatings and Films Electronic Optical and Magnetic Materials Atomic diffusion Diffusion layer Crystallography Materials Chemistry Grain boundary diffusion coefficient Effective diffusion coefficient Diffusion (business) |
| Zdroj: | Thin Solid Films. 44:217-231 |
| ISSN: | 0040-6090 |
| DOI: | 10.1016/0040-6090(77)90457-6 |
| Popis: | Diffusion in films is found to have complications that are either absent or less obvious in the case of diffusion in bulk samples. This results largely from the presence of at least one surface always near the diffusion zone. Long term diffusion treatments at 900°C with a sample containing a 2.8 υ Ni electroplating on a Cu single-crystal substrate were found to give diffusion coefficients with a strong time dependence amounting to a reduction of more than one-tenth of the original value. For short times, the influence of grain boundaries must be considered in the diffusion model. However, after a diffusion time equal to or greater than 75 min, the diffusion model simplifies to the one-dimensional case with enhancement factors for grain boundary and dislocation pipe diffusion. At these later times, it is shown that the diffusion coefficient is well approximated by the sum of lattice, grain boundary and pipe diffusion coefficients. The instantaneous diffusion coefficient depends upon the rate at which dislocations are generated and the rate of “clogging” by impurity atoms. The removal of mechanical constraints and the near source of impurity atoms as a result of at least one surface will influence the generation and distribution of new pipes as well as the rate of clogging. Diffusion coefficients are presented as a function of time which are above, very near and below recent values given in the literature for bulk specimens. Also, simultaneous measurements of the defect structures enable the lattice, grain boundary and dislocation pipe diffusion coefficients to be separated. |
| Databáze: | OpenAIRE |
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