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U.S. Department of Energy
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INVESTIGATION OF DIFFUSION BARRIERS FOR REFRACTORY METALS

Technical Report ·
OSTI ID:4772905

Thirty-three base barrier combinations involving the four refractory metals W, Mo, Ta, and Nb and 12 potential barrier metals having melting points over 1700 deg C were evaluated for relative interdiffusion behavior at 1700 and 1800 deg C. The relative extent of interdiffusion decreased with increasing base- barrier solidus temperature, although wide variations occurred for melting points up to 2100 deg C. Interdiffusion in the-Mo--Cr combination was found to be substantially reduced by the presence of a Re barrier. Re, Ru, and Ir barriers appeared optimum for W base metal; W, Re, Ru, and Ir appeared optimum for Ta; and W, Re, Os, and Zr appeared optimum for Nb. 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 Nb--Re combinations was found to increase with time (t) in accordance with the relationship X/sup n/ = kt, with values of n in the range 1.4 to 4.9. (auth)

Research Organization:
ManLabs, Inc., Cambridge, Mass.
NSA Number:
NSA-17-001918
OSTI ID:
4772905
Report Number(s):
ASD-TDR-62-432
Country of Publication:
United States
Language:
English