Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Influences of phase transition and microstructure on dielectric properties of ceramics | Jaiban et al. Nanoscale Research Letters 2012 7 45 http content 7 1 45 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Influences of phase transition and microstructure on dielectric properties of ceramics Panupong Jaiban1 Ampika Rachakom1 Sukanda Jiansirisomboon1 2 and Anucha Watcharapasorn1 2 Abstract Bismuth sodium zirconate titanate ceramics with the formula BNZT where x and were prepared by a conventional solid-state sintering method. Phase identification was investigated using an X-ray diffraction technique. All compositions exhibited complete solubility of Ti4 at the Zr4 site. Both a decrease of unit cell size and phase transition from an orthorhombic Zr-rich composition to a rhombohedral crystal structure in a Ti-rich composition were observed as a result of Ti4 substitution. These changes caused dielectric properties of BNZT ceramics to enhance. Microstructural observation carried out employing SEM showed that average grain size decreased when addition of Ti increased. Grain size difference of BNZT above mole fraction of Ti4 displayed a significant increase of dielectric constant at room temperature. Keywords ceramics X-ray diffraction electron microscopy crystal structure electrical properties Background Nowadays materials possessing a diffuse phase transition at high temperature are of interest because they are believed to be a promising candidate for various electronic devices. Examples are multilayer capacitors detectors MEMs sensors actuators etc. However high permittivity at room temperature is also significant. Recently Lily et al. 1 have successfully fabricated and investigated a novel perovskite-type ceramic of Bi 5Na r5ZrO3 BNZ compound. They reported that the mentioned ceramic had an orthorhombic structure and a high curie temperature of 425 C. This value is rather high when compared with well-known lead-free ceramics such as .
