SIMS study of transition metal transport in single crystalline yttria stabilised zirconia

Abstract

The diffusion of Co, Fe and Ni in single crystalline yttria stabilized zirconia (YSZ) containing 9.5 mol% Y₂O₃ was studied in the temperature range between 1373 and 1673 K using secondary ion mass spectroscopy. Two different types of diffusion sources were used: thin oxide layers made by spin coating with a thickness of about 150 nm containing all three transition metals (Fe, Co and Ni) on YSZ single crystals and YSZ single crystals implanted with Ni (3 × 10¹⁶ ions cm⁻², 100 keV) at a mean depth of 45 nm. The determined diffusivities varied in the order D(Fe) < D(Co) < D(Ni). Activation energies for the diffusion of the elements were determined to be 2.7 ± 0.4 eV, 3.9 ± 0.3 eV and 3.8 ± 0.3 eV for Fe, Co and Ni (3.6 ± 0.5 eV for implanted Ni), respectively. For the latter ion, the value of the activation energy was practically independent of the type of Ni source. The values for all elements were lower by 1–2 eV than for the host cation (Y and Zr) diffusion.