• PDF / 367,002 Bytes
• 6 Pages / 432 x 648 pts Page_size
• 70 Downloads / 238 Views

DOWNLOAD

REPORT

---

Fabrication of 0.6(Bi0.85La0.15)FeO3-0.4PbTiO3 Multiferroic Ceramics by Tape Casting Method Guoxi Jin, Jianguo Chen, Shundong Bu, Dalei Wang, Rui Dai and Jinrong Cheng* School of Materials Science and Engineering, Shanghai University, 200072, P.R. China * corresponding author: [email protected] ABSTRACT The 0.6(Bi0.85La0.15)FeO3-0.4PbTiO3 (BLF-PT) ceramics were prepared by tape casting method. Effects of binder (polyvinylbutyl dibutyl PVB), plasticizer (phthalate-polyethylene glycol DBP-PEG) and dispersant (triethylolamine, TEA) concentration on the rheological properties of BLF-PT slurry were investigated. The optimized component ratio for ceramics powders, binder, plasticizer, dispersant and solvent (ethanol, EtOH) in the slurry was 50 wt.%, 4 wt.%, 6 wt.%, 1 wt.% and 39 wt.%. The dielectric constant İr, loss tanį, and remnant polarization Pr of BLF-PT ceramics laminated from the tapes were 525 (1 kHz), 1.7% (1 kHz) and 30 ȝC/cm2 (45 kV/cm), respectively, which were comparable to those of BLF-PT ceramics prepared by traditional solid state reaction method. INTRODUCTION Tape casting method is capable of fabricating flexible and low-cost thick films with widest thickness range [1]. Compared with conventional process, tape casting owns the great advantage in forming large-area, thin and flat ceramic parts. And it has been widely used in electronics industry for capacitors, piezoelectric and electrostrictive devices, ferromagnetic memories, ceramic substrates, fuel cells and so on. The tape casting process involves casting the slurry onto a flat carrier surface [2]. The slurry usually consists of ceramic powders with appropriate additions of solvents, plasticizers, dispersants and binders. The solvents evaporate to leave a relatively dense flexible sheet or ceramic tape that may be stored on rolls or stripped from the carrier in a continuous process [3]. Recently, materials based on the BiFeO3-PbTiO3 (BF-PT) system have drawn considerable attentions because of their high Curie temperature and the coexistence of ferroelectric and ferromagnetic orderings in single phase at room temperature, exhibiting potential applications in spintronics, information storage, sensing and actuation devices [4-7]. However, low resistivity and weak ferromagnetic property at room temperature makes it difficult to be used in practical applications [8-10]. Our previous work showed that La modified BF-PT ceramics exhibited enhanced multiferroic and highly insulated properties simultaneously at room temperature [11]. In this paper, La modified BF-PT ceramics were synthetized by tape casting method. Effects of binder, plasticizer, and dispersant concentrations on the rheological properties of BLF-PT slurry were discussed, and then electrical properties of ceramics derived form the tapes were characterized.

61

EXPERIMENT Analytical-grade powders of Bi2O3, TiO2, La2O3, Fe2O3 and PbO were used as starting materials to synthetize 0.6(Bi0.85La0.15)FeO3-0.4PbTiO3 solid solution. Firstly, they were blended and adequately ball-milled with deionized