In:
Journal of the American Ceramic Society, Wiley, Vol. 77, No. 8 ( 1994-08), p. 2154-2156
Abstract:
Using an ordinary ceramic processing technique, a new method of preparing porous BaTiO 3 , PTC thermistors is introduced. Adding proper graphite powders into calcined BaTiO 3 , powder can increase porosity and enhance the PTC effect of the sintered sample. When the graphite addition is about 1.0 wt%, the resisivity of samples from low‐purity raw materials decreases to 20 Σ·cm at room temperature, while the PTC resistivity ratio is over 10 5 and 1–2 orders higher than that of samples without the porosifier. The porosifier has increased the reproducibility of resistivity from 60% up to 90%. In addition, the porous thermistor has a fast response to overcurrent and shows some improvement in heat resistance. With the aid of the Heywang model and the Kuwabara conclusion, the influence of graphite on grain surfaces is discussed. The experimental results show that this method is a useful technique to prepare good PTC thermistors from low‐purity raw materials.
Type of Medium:
Online Resource
ISSN:
0002-7820
,
1551-2916
DOI:
10.1111/jace.1994.77.issue-8
DOI:
10.1111/j.1151-2916.1994.tb07111.x
Language:
English
Publisher:
Wiley
Publication Date:
1994
detail.hit.zdb_id:
2008170-4
detail.hit.zdb_id:
219232-9
Permalink
