Effect of ZnO on the microstructure and electrical properties of WO3–Bi4Ti3O12 ceramics

✍ Scribed by M. Villegas; T. Jardiel; A.C. Caballero

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 942 KB
• Volume: 29
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2008.06.026

✦ Synopsis

The aim of the present work is to explore the possibility of incorporate a small amount of ZnO to improve the microstructure control of W-doped BIT-based materials. Two different processing routes have been used according to previous results reported for other materials: reaction and sintering in one single step and a previous calcination step. The sintering behaviour of the samples, the obtained crystalline phases and the microstructure analysis indicate that the reaction between ZnO and Bi 2 O 3 plays a critical role during sintering. Both Bi 2 Ti 2 O 7 and Zn 2 TiO 4 secondary phases are stabilized when adding ZnO. Actually, when WO 3 and ZnO are incorporated simultaneously to BIT materials, they interact stabilizing the Bi 2 Ti 2 O 7 phase and avoiding the incorporation of W 6+ into the BIT lattice. As a consequence, the electrical conductivity of the samples with ZnO is two orders of magnitude higher than that of the samples doped only with WO 3 , suggesting that WO 3 does not form a solid solution with BIT. The curve dielectric constant vs temperature also reveals the role played by the Bi 2 Ti 2 O 7 phase.