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AN INVESTIGATION OF DIFFUSION IN THE COLUMBIUM VANADIUM SYSTEM.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO
Diffusion rates in the Cb-V system were investigated using electron microprobe analysis of the diffusion zones to determine concentration gradients. The interdiffusion coefficient, D, was found using a computer program to solve the Matano-Boltzman method. Activation energies, Q, and frequency factors, Do, were derived from values of D at the same concentrations but at different temperatures. A partial list of Do and Q for interdiffusion in lattice parameter measure as a function of composition is 5 ao Cb Q 59.8 Kcalmol, Do 5.3x10 to the 16th power 1 sq Phr 55 ao Cb Q 48.1 Kcalmol, Do 9.5x10 to the 14th power 1 sq Phr 95 ao Cb Q 69.4 Kcalmol, Do 7.0x10 to the 15th power 1 sq Phr. Movement of tungsten Kirkendall markers at 12.7 ao Cb and 1404C. during the diffusion anneal indicated D sub V D sub Cb. Diffusion in the Cb-V system is apparently by a vacancy mechanism. Author