Impedance spectroscopy study of Na2Nb4O11 ceramic matrix by the addition of Bi2O3

• Published in: Journal of alloys and compounds Vol. 584; pp. 295 - 302
• Main Authors: Oliveira, R.G.M., Romeu, M.C., Costa, M.M., Silva, P.M.O, Filho, J.M.S., Junqueira, C.C.M., Sombra, A.S.B.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 2014; Elsevier
• Subjects: Alloys; Binders; Ceramics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity; Dielectric ceramics; Dielectric properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Frequency ranges; Impedance; Impedance spectroscopy; Microwaves; Physics; Radio frequencies; Sodium niobate; Conductivity; Impedance; Sodium niobate; Dielectric ceramics; Impurity density; Microwave radiation; Sodium niobates; XRD; Lattice parameters; Radiofrequency; Complex impedance; Bismuth additions; Temperature effects; Sintering; Solid state reaction
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2013.08.208

•The structural, dielectric properties of the addition in the Na2Nb4O11.•Complex impedance has been used to analyze the electrical and dielectric properties.•The modulus curves show a non-Debye behavior. The effects of different additions of Bi2O3 (0, 2, 5 and 10wt.%) on Na2Nb4O11 ceramics have been studied by complex impedance spectroscopy analysis. The structural and dielectric properties of Na2Nb4O11ceramics with Bi2O3 additions are also discussed as a possible material for microwave and radio frequency applications. Solid state reaction method was used for producing the target compound. The present work also reports on sample preparation, where polyvinyl alcohol was used as a binder to reduce the brittleness and the organic binder was burnt out during sintering process. X-ray diffraction at room temperature was used to identify phases formed as well as optimum calcinations conditions the production of Na2Nb4O11 powder. Analysis was carried out to identify the pure-phase specimen by Rietveld refinement method. Based on this method a structure with the lattice parameters (a=10.840Å, b=6.162Å and c=12.745Å; α=90°, β=106.4° and γ=90°) was found. The dielectric and electrical properties of Na2Nb4O11 for appropriate amounts of Bi2O3 additions has showed a considerable enhancement and overriding applications for microwave and radio frequency communications. The electrical behavior (complex impedance Z*, complex modulus M*) were studied over a frequency range (1Hz to 1MHz) and temperature (553–713K).