The effect of adding Ba2TiSi2O8 to the pure or Mn-doped titanate was studied by means of high-temperature conductivity measurements and analytical electron microscopy. The diffusivity (tables 21 and 22) was deduced from the resistivity changes which occurred during changes in the O partial pressure. The results showed that the additive precipitated, during cooling, as a second crystalline phase. Only a small amount of amorphous phase remained in a few grain boundaries. The secondary crystalline phase incorporated excess Mn which was left over from the heterogeneous doping of the titanate.
J.Weiss, G.Rosenstein: Journal of Materials Science, 1988, 23[9], 3263-71
Table 21
Diffusion of O in BaTiO3 with Various Additions
Addition | Content (wt%) | Temperature (C) | Process | D (cm2/s) |
- | - | 810 | out-diffusion | 6.9 x 10-5 |
- | - | 905 | out-diffusion | 1.5 x 10-4 |
- | - | 905 | in-diffusion | 6.6 x 10-5 |
- | - | 998 | out-diffusion | 2.0 x 10-4 |
- | - | 998 | in-diffusion | 4.2 x 10-4 |
Si2Mn0.05O8.1 | 1 | 815 | out-diffusion | 6.6 x 10-5 |
Si2Mn0.05O8.1 | 1 | 908 | out-diffusion | 1.5 x 10-4 |
Si2Mn0.05O8.1 | 1 | 908 | in-diffusion | 5.1 x 10-6 |
Si2Mn0.05O8.1 | 1 | 995 | out-diffusion | 1.3 x 10-4 |
Si2Mn0.05O8.1 | 1 | 995 | in-diffusion | 1.7 x 10-4 |
Si2Mn0.05O8.1 | 8 | 815 | out-diffusion | 4.5 x 10-5 |
Si2Mn0.05O8.1 | 8 | 815 | in-diffusion | 1.4 x 10-5 |
Si2Mn0.05O8.1 | 8 | 907 | out-diffusion | 5.3 x 10-5 |
Si2Mn0.05O8.1 | 8 | 907 | in-diffusion | 1.0 x 10-5 |
Si2Mn0.05O8.1 | 8 | 995 | out-diffusion | 6.3 x 10-5 |
Si2Mn0.05O8.1 | 8 | 995 | in-diffusion | 4.0 x 10-5 |