DIFFUSION OF POINT DEFECTS IN CALCIUM TITANATE

Single crystal samples of calcium titanate were equilibrated with water-hydrogen atmospheres of a known PH2O{plus 45 degree rule}PH2, ratio at temperatures of 1100°, 1200° and 1300°C. After a step in the PH2O{plus 45 degree rule}PH2 ratio over the sample, the electrical conductivity was measured continuously until a new equilibrium was attained. Diffusion coefficients were determined by analysis of the transient electrical conductivity data. The effective diffusion coefficient at 1200°C and PH2O{plus 45 degree rule}PH2 = 10-3 was 5.2 × 10-6 cm2sec-1; the enthalpy of motion of oxygen vacancies was 13,000 cal{plus 45 degree rule}mol. © 1969.