The diffusion coefficients of oxygen were measured in TiC0.97 single crystals by using a gas exchange technique in which the amount of stable isotope taken up by the carbide was controlled by introducing a constant gas volume of oxygen-marked carbon monoxide. Diffusion was extended over depths of 1 to 150μm. The concentration profiles were measured by means of secondary ion mass spectroscopy. A constant superficial concentration was assumed. The results could be described by:

D(cm2/s) = 4.8 x 10-1exp [-3.97(eV/atom)/kT]

at 1500 to 2100C. At 1000 to 1500C, the diffusion coefficients exhibited a departure from the high-temperature extrapolated data. This was interpreted as being due to an enhancement of the oxygen diffusivity by dislocations.

Oxygen Diffusion in Titanium Carbide. M.Schuhmacher, P.Eveno: Solid State Ionics, 1984, 12[C], 263-70