Radiotracer and serial sectioning methods were used to study the diffusion of 65Zn isotope in ferrites at between 1130 and 1280C in air. In general, the diffusion profiles exhibited fast and slow regimes. At below 1280C, the diffusion coefficients changed monotonically; depending upon the composition of the ferrite. In the solid solution, cation diffusion occurred much more slowly and with a higher activation energy than in the end-members. The results (table 95) indicated that, in Zn-containing ferrites, the cation diffusion was governed by the preliminary treatment which was given to the samples.
M.V.Slinkina, V.M.Zhukovskii: Izvestiya Akademii Nauk SSSR - Neorganicheskie Materialy, 1988, 24[11], 1883-6. (Inorganic Materials, 1988, 24[11], 1609-12)
Table 95
Diffusion Parameters for Zn in (Ni,Zn)Fe2O4 Ferrites
between 1130 and 1280C
Ferrite | Do (cm2/s) | E (kJ/mol) |
ZnFe2O4 | 1.6 x 106 | 450 |
ZnFe2O4 | 2.8 x 1011 | 612 |
Ni0.6Zn0.4Fe2O4 | 7.9 x 106 | 474 |