Temperature stable K_0.5(Nd_1−xBi_x)_0.5MoO₄ microwave dielectrics ceramics with ultra‐low sintering temperature

Abstract

K 0.5 (Nd 1Àx Bi x ) 0.5 MoO 4 (0.2 ≤ x ≤ 0.7) ceramics were prepared via the solid-state reaction method. All ceramics densified below 720°C with a uniform microstructure. As x increased from 0.2 to 0.7, relative permittivity (ɛ r ) increased from 13.6 to 26.2 commensurate with an increase in temperature coefficient of resonant frequency (TCF) from -31 ppm/°C to + 60 ppm/°C and a decrease in Qf value (Q = quality factor; f = resonant frequency) from 23 400 to 8620 GHz. Optimum TCF was obtained for x = 0.3 (À15 ppm/°C) and 0.4 (+4 ppm/°C) sintered at 660 and 620°C with ɛ r~1 5.4, Q f~1 9 650 GHz, and ɛ r~1 7.3, Q f~1 3 050 GHz, respectively. Ceramics in this novel solid solution are a candidate for ultra low temperature co-fired ceramic (ULTCC) technology.

Preparation, characterization, thermal, and electrical properties of chlorinated ethylene propylene diene monomer/hydroxyapatite nanocomposites

“…Hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) nanoparticles were prepared by a simple co-precipitation technique [18]. Equimolar concentrations of CaCl 2 and (NH 4 ) 2 HPO 4 were prepared in an aqueous solution and these solutions were preheated, mixed under vigorous stirring.…”

Tunable microwave dielectric properties in SrO‐V2O5 system through compositional modulation

“…The high sintering temperature (>1000°C) and relatively large positive τ f value (~ +63.5 ppm/ ° C), however, still limit its potential utilization in low temperature cofired ceramics (LTCC) application in which the ceramic layers should be cofired with the inner electrodes (generally silver) . Thus, reduction in sintering temperature to below the melting temperature of silver (961°C) and tailoring τ f to near‐zero is necessary for M 3 (VO 4 ) 2 …”

“…22 Thus, reduction in sintering temperature to below the melting temperature of silver (961°C) and tailoring τ f to near-zero is necessary for M 3 (VO 4 ) 2 . [23][24][25] According to the binary phase diagram of SrO-V 2 O 5 , there are two stable phases Sr 2 V 2 O 7 with triclinic structure and Sr 3 (VO 4 ) 2, and both of the phases can coexist. 26 Importantly, one of the advantages of Sr 2 V 2 O 7 is its negative τ f value ~ −34.8 ppm/°C which can behave as a τ f compensator for Sr 3 (VO 4 ) 2 .…”

Preparation and Microwave Dielectric Properties of Ba3A(V2O7)2 (A = Mg, Zn) Ceramics for ULTCC Applications

“…In ULTCC materials, the ceramics are co‐fired with aluminium electrode which has the melting point of 660 °C. Only a few ceramic systems based on tellurium,, molybdenum and vanadium with good dielectric properties are reported in literature for ULTCC applications. In the present work, phase pure and ultra low temperature sinterable Ba 3 Mg(V 2 O 7 ) 2 (BMV) and Ba 3 Zn(V 2 O 7 ) 2 (BZV) ceramics have been prepared through solid state ceramic route.…”