Influence of Bi3+ions in enhancing the magnitude of positive temperature coefficients of resistance in n-BaTiO3ceramics

✍ Scribed by P. Padmini; T. R. N. Kutty

• Publisher: Springer US
• Year: 1994
• Tongue: English
• Weight: 663 KB
• Volume: 5
• Category: Article
• ISSN: 0957-4522
• DOI: 10.1007/bf00186186

✦ Synopsis

Bi 3+ ions substituting at Ba-sites in a limited concentration range with another donor dopant occupying the Ti-sites in polycrystalline BaTiOa enhanced the positive temperature coefficient of resistance (PTCR) by over seven orders of magnitude. These ceramics did not require normal post sinter annealing or a change to an oxygen atmosphere during annealing. These ceramics had low porosities coupled with better stabilities to large applied electric fields and chemically reducing atmospheres. Bi a+ ions limited the grain growth to less than 8 gm in size, they enhanced the concentration of accepter-type trap centres at the grain-boundary-layer regions and maintained complete tetragonality at low grain sizes in BaTi03 ceramics.