Abstract
Indium oxide based ceramics with bismuth oxide addition were sintered in air in the temperature range 800-1300 ??C. Current-voltage characteristics of In2O3-Bi2O 3 ceramics sintered at different temperatures are weakly nonlinear. After an additional heat treatment in air at about 200 ??C samples sintered at a temperature within the narrow range of about 1050-1100 ??C exhibit a current limiting effect accompanied by low-frequency current oscillations. It is shown that the observed electrical properties are controlled by the grain-boundary barriers and the heat treatment in air at 200 ??C leads to the decrease in the barrier height. Electrical measurements, scanning electron microscopy and X-ray photoelectron spectroscopy results suggest that the current limiting effect observed in In2O3-Bi2O3 may be explained in terms of a modified barrier model; the observed current limiting effect is the result of an increase of barrier height with increasing electric field, due to additional oxygen absorption. It is found that In2O3-Bi2O3-Co3O 4-Cr2O3 ceramic exhibits current-voltage characteristics with negative differential resistance due to Joule microheating. ?? 2009 Elsevier Ltd. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 539-544 |
| Number of pages | 6 |
| Journal | Journal of the European Ceramic Society |
| Volume | 30 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2010 |
Keywords
- A. Sintering
- B. Grain boundaries
- Bismuth
- C. Electrical properties
- Ceramic materials
- Chromium
- Current voltage characteristics
- Electric fields
- Electric properties
- E. Varistors
- Grain boundaries
- Grain size and shape
- Indium
- Indium oxide
- Metal analysis
- Negative resistance
- Oxygen
- scanning electron microscopy
- Sintering
- Thermal effects
- Varistors
- X ray photoelectron spectroscopy