Effect of CoO additive on structure and electrical properties of (Na0.5Bi0.5)0.93Ba0.07TiO3 ceramics prepared by the citrate method

✍ Scribed by Qing Xu; Min Chen; Wen Chen; Han-Xing Liu; Bok-Hee Kim; Byung-Kuk Ahn

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 786 KB
• Volume: 56
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2007.10.014

✦ Synopsis

Na 0.5 Bi 0.5 ) 0.93 Ba 0.07 TiO 3 ceramics with added 0-0.8 wt.% CoO were prepared by a citrate method and the influence of the CoO additive on the structure and electrical properties of the ceramics was investigated. All the specimens maintained a rhombohedral-tetragonal phase coexistence in crystal structure and the addition of CoO caused a remarkably promoted grain growth. Adding CoO led to a disappearance of the response in the dielectric constant (e r ) to the ferroelectric-antiferroelectric transition and increased the diffuseness of the dielectric constant peak around 230 °C. Polarization-electric field hysteresis loops at varied temperatures revealed that adding CoO served to increase the depolarization temperature (T d ). The addition of CoO tailored the dielectric, piezoelectric and ferroelectric properties at room temperature basically following a hard doped effect. The specimen with 0.8 wt.% CoO added showed a low dissipation factor (tan d) of 0.8% and a high mechanical quality factor (Q m ) of 297 while retaining a piezoelectric constant (d 33 ) of 137 pC N À1 .