Oxygen self-diffusion in cerium oxide doped with Nd

Polycrystalline Ce0.77Nd0.23O1.885 having a relative density in excess of 98% was prepared. Oxygen diffusion experiments were performed for the temperature range from 750 to 1100 degreesC, in an oxygen partial pressure of 6.6 kPa. The concentration profile of O-18 in the specimens following diffusion annealing was measured by secondary ion mass spectroscopy (SIMS). The oxygen self-diffusion coefficient obtained using secondary ion mass spectrometry was expressed by D = 6.31 x 10(-9) exp(-53 kJ mol(-1)/RT) m(2) s(-1) and was in the extrinsic region. The oxygen diffusion coefficient of Ce0.77Nd0.23O1.885 was larger than that of Ce0.8Y0.2O1.90; it was close to those of Ce0.6Y0.4O1.80 and Ce(0.69)Gcb(0.31)O(2-delta). The oxygen diffusion coefficient obtained by the tracer method at 700 OC agreed with that calculated from the electrical conductivity in Ce0.77Nd0.23O1.885. The activation energy of the surface exchange coefficient was 94 kT mol(-1), and the values of the surface exchange coefficient were similar to those of stoichiometric CeO2 and ThO2.