Direct Measurement of Titanium Pipe Diffusion Coefficients in Sapphire

Abstract

The diffusion behavior of Ti3+ along basal dislocations in sapphire has been investigated by SIMS technique. High-density unidirectional dislocations were introduced by the high-temperature mechanical deformation, and Ti3+ ions were subsequently diffused along the dislocations. The SIMS diffusion profiles clearly showed diffusion tail due to the short circuit diffusion along the dislocations called pipe diffusion. Lattice diffusion coefficient and pipe diffusion coefficient of Ti3+ at 1300°C were measured to be 1.0±0.2×10-19 [m2/sec] and 2.0±0.6× 10-13 [m2/sec], respectively.