Microstructure and PTCR characteristics of porous BaTiO3-based ceramics prepared by adding activated carbon

• Published in: Metals and materials international Vol. 18; no. 5; pp. 887 - 893
• Main Authors: Lee, Ki-Ju, Cho, Won-Seung
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2012; Springer Nature B.V; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Engineering Thermodynamics; Heat and Mass Transfer; Machines; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Metallic Materials; Processes; Solid Mechanics; 재료공학; activated carbon; porous materials; sintering; grain boundary; electrical conductivity/resistivity
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-012-5022-7

As a pore precursor, activated carbon of different contents (0 to 30 vol%) was added to (Ba,Sr)TiO 3 powder. Porous (Ba,Sr)TiO 3 ceramics were prepared by pressureless sintering at 1350 °C for 1 h in air. The effects of the activated carbon content on the microstructure and positive temperature coefficient of resistivity (PTCR) characteristics in porous (Ba,Sr)TiO 3 ceramics were investigated. The porosity of the porous (Ba,Sr)TiO 3 ceramics increased from 6.5% to 33.5%. The PTCR jump of the porous (Ba,Sr)TiO 3 ceramics prepared with activated carbon was > 10 5 and increased slightly with increasing activated carbon concentration. These results correspond to the Heywang model of the PTCR effect in (Ba,Sr)TiO 3 ceramics, suggesting that activated carbon is an effective additive for preparing porous BaTiO 3 -based ceramics. The newly prepared (Ba,Sr)TiO 3 ceramics can be used as a gas sensor.