Phase evolution, phase transition, and microwave dielectric properties of scheelite structured xBi(Fe1/3Mo2/3)O4–(1−x)BiVO4 (0.0 ≤ x ≤ 1.0) low temperature firing ceramics

Abstract

In the present work, the xBi(Fe 1/3 Mo 2/3 )O 4 -(1Àx)BiVO 4 (0.0 # x # 1.0) ceramics were prepared via the solid state reaction method. All the ceramics can be densified at low sintering temperatures around 820 C. At room temperature, the BiVO 4 type scheelite monoclinic solid solution was formed in ceramic samples with a composition of x # 0.10. When x lies between 0.1 and 0.7, a BiVO 4 scheelite tetragonal phase is formed at room temperature. In the range 0.7 # x < 0.9, the ceramic samples were found to be composites consisting of BiVO 4 type tetragonal and Bi(Fe 1/3 Mo 2/3 )O 4 type monoclinic scheelite phases, and when x $ 0.9, the Bi(Fe 1/3 Mo 2/3 )O 4 type monoclinic scheelite solid solution was formed. In the BiVO 4 type monoclinic solid solution region, the phase transition to tetragonal phase was studied by in situ Raman and Far-Infrared spectroscopies and by thermal expansion analysis. All of these methods indicated that the phase transition temperature almost linearly decreased from 255 C for pure BiVO 4 to about À9 C for x ¼ 0.1 sample. High performance microwave dielectric properties with a high permittivity of about 74.8, high Qf values above 11 500 GHz, and a small temperature coefficient of resonant frequency within +20 ppm per C in a wide temperature range of 20-140 C can be obtained in the composite ceramic sample with 60 mol% x ¼ 0.10 composition and 40 mol% x ¼ 0.02 composition. The xBi(Fe 1/3 Mo 2/3 )O 4 -(1Àx)BiVO 4 (0.0 # x # 1.0) ceramics might provide useful candidate materials for microwave integrated capacitive devices, such as filters, antennas, etc.

Crystal Structure and Microwave Dielectric Properties of an Ultralow‐Temperature‐Fired (AgBi)0.5WO4 Ceramic

“…In our previous work, [3,[8][9][10][11][12] a series of ultralow-temperature-firing microwave dielectric ceramics with low (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), medium , and high k values (Ͼ40) have been explored. Among them, Bi 2 Mo 2 O 9 seems to be very promising owing to its ultralow sintering temperature of ca.…”

Novel temperature stable high-εrmicrowave dielectrics in the Bi2O3–TiO2–V2O5system

“…[1][2][3][4] Many classic microwave dielectric ceramics based on ABO3 perovskite structure have been explored and the relation between structure-property has been extensively studied. 5,6 Recently, many complex oxides with classic ABO4 type, such as scheelite (CaMoO4, BiVO4), 7,8 Fergusonite (LaNbO4, NdNbO4), 9 stibiotantalite (BiNbO4, BiTaO4), 10,11 wolframite (ZnWO4, MgWO4), 12 zircon (CeVO4) 13 and rutile ((Zn,Nb)TiO4, (Cu,Nb)TiO4) 14 lattice. In the present work, a comprehensive study on the phase assemblage and evolution in (Bi,Y)VO4 system was performed with the zircon-type solid solution region and its associated sintering behavior, microstructure and microwave dielectric properties were studied in detail.…”

Microwave dielectric properties of bismuth-substituted Ba3.75Nd9.5Ti17Al4/3O54 ceramics

“…Therefore, research on both sites' simultaneous replacement was an effective way to overcome the shortcomings of those separate substitution. Also due to the fact that many other studies has reported the positive effects of single Bi substituting (0.05 B x) at Nd site on the system, goals of the investigation were to study the impact of substitution in Al-replaced Ba 3.75 Nd 9.5 Ti 18 0 54 (0.05 B x B 0.2) ceramic on microwave dielectric properties and to find a proper x value range that would conduct good dielectric properties [7][8][9][10].…”