INFLUENCE OF CONTAMINATION ON DIFFUSION OF POINT-DEFECTS IN RUTILE REDUCED IN VACUUM

The diffusion coefficients of point defects in the reduced rutile were determined by a theory of diffusion in a plane sheet with an equal surface concentration and a uniform initial distribution of solute in a sheet. These coefficients obtained in vacuum by a diffusion pump varied with the reduction time and this tendency was more remarkable in the case of a trapless diffusion pump. But the diffusion coefficients obtained in the case of an ion pump were nearly constant at any reduction temperature independent of the reduction time except for the beginning stage. It appears that the differences are due to the contamination introduced by the diffusion pump.