INVESTIGATION OF DIFFUSION BARRIERS FOR REFRACTORY METALS
Abstract
Thirty-three base barrier combinations involving the four refractory metals: W, Mo, Ta, Cb; and 12 potential barrier metals having melting points over 1700 C were evaluated for relative interdiffusion behavior at 1700 C. Further evaluation of promising W and Ta-base combinations was carried out at 1800 C. In general, the relative extent of interdiffusion decreases with increasing basebarrier solidus temperature, although wide variations occur for melting points up to 2100 C. The thickness (X) of the total interdiffusion zone as well as of the intermediate phase layers in the W-Re, Mo-Re, Ta-Re, and Cb- Re combinations was found to increase with time (t) in accordance with X(n) = kt, with values of n in the range 1.4 to 4.9. Approximate over-all interdiffusion coefficients, D sub s, of 3.4 x 10 to the 6th power, 9.0 x 10 to the 5th power, 1.9 x 10 to the 8th power, and 5.1 x 10 to the 8th power sq cm/sec were found for the W-Re, Mo-Re, Ta-Re, and Cb-Re combinations, respectively.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1962
- Accession Number
- AD0285569
Entities
People
- B. S. Lement
- E. M. Passmore
- J. E. Boyd