The grain-boundary diffusion coefficient of strontium in La0.9Ca0.13CrO3-δ was determined using secondary-ion mass spectrometry and two different measurement modes: depth profiling from the surface and line scanning on the fracture surface. Depth profiles that were sputtered by an O2+ primary-ion beam gave two slopes for the strontium concentration profile; corresponding to bulk and grain-boundary diffusion. The depth profiles were fitted to an appropriate equation that gave the diffusion coefficients: Dbulk = 6.5 x 10-20 and Dgb = 1.6 x 10-15m2/s in air at 1273K. To obtain Dgb via SIMS line-scanning measurements, the fracture surface of La0.9Ca0.13CrO3-δ was measured using a low-energy O2+ primary-ion beam. The line-scanning measurements permitted determination of the strontium concentration profiles around the grain boundary. The Dgb value that was obtained via the line-scanning mode was 6.0 x 10-13m2/s; which was a factor of 100 greater than that which was obtained using the depth-profile mode.

Grain-Boundary Diffusion of Strontium in (La,Ca)CrO3 Perovskite-Type Oxide by SIMS. T.Horita, N.Sakai, T.Kawada, H.Yokokawa, M.Dokiya: Journal of the American Ceramic Society, 1998, 81[2], 315-20