The phase diagram, and the conductivity of various compositions, were determined. It was noted that KBr was soluble in NaI to the extent of 20mol% at 30C, whereas the solubility of NaI in KBr was less than 10mol% at the same temperature. Complete solid solubility occurred only at temperatures of more than 400C. The maximum enhancement of the conductivity at 500C was represented by a factor of 500 with respect to pure KBr, or by a factor of 8 with respect to pure NaI (table 28). This maximum occurred at 70mol%NaI. The results were explained in terms of so-called lattice-loosening.
P.Manoravi, K.Shahi: Journal of the Physics and Chemistry of Solids, 1991, 52[3], 527-35
Table 28
Ionic Conduction Parameters for the KBr-NaI System
NaI (mol%) | Temperature (C) | σo (S/cm) | Q (eV) |
0 | 595-720 | 9550 | 1.58 |
10 | 540-650 | 7590 | 1.43 |
20 | 480-595 | 1000 | 1.20 |
30 | 405-560 | 8320 | 1.29 |
40 | 400-540 | 3390 | 1.20 |
50 | 400-540 | 38000 | 1.34 |
60 | 330-522 | 110000 | 1.37 |
70 | 390-520 | 87000 | 1.31 |
80 | 410-527 | 85100 | 1.34 |
90 | 400-570 | 53700 | 1.35 |
100 | 445-615 | 28900 | 1.38 |