The grain-boundary-diffusion coefficient (Dgb) of strontium in La0.9Ca0.13CrO3-δ was determined by secondary-ion mass spectrometry (SIMS), using two different measurement modes: depth profiling from the surface and line scanning on the fracture surface. The depth profiles that were sputtered by an O2+-primary-ion beam gave two slopes of strontium concentration profiles, which corresponded to grain (bulk) and grain-boundary diffusion. The depth profiles were fitted to an appropriate equation that gave the grain- (bulk-) and grain-boundary-diffusion coefficients (Dbulk = 6.5 × 10-20 m2/s and Dgb = 1.6 × 10-15 m2/s in air at 1273 K, respectively). Initially, to obtain the Dgb value via the SIMS line-scanning measurement, the fracture surface of La0.9Ca0.13CrO3-δ was measured by a low-energy O2+-primary-ion beam. The line-scanning measurement enabled us to successfully determine the strontium concentration profiles around the grain boundary. However, the Dgb value that was obtained via the line-scanning mode was 6.0 × 10-13 m2/s, which was a factor of 100 greater than that which was obtained by the depth-profile mode. Comparison between the depth-profile and line-scanning modes will require additional careful examination.
|Number of pages||6|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 1998 Feb|