Low-temperature sintering and microwave dielectric properties of Mg4Nb2O9 ceramics

Abstract

The effects of V 2 O 5 and Li 2 CO 3 on the sinterability and microwave dielectric properties of Mg 4 Nb 2 O 9 (MN) ceramics were investigated. With addition of 1.5wt% V 2 O 5 , the dielectric constant (e) and Q · ƒ value of MN ceramics sintered at 1,000°C are comparable to those of pure MN sintered at 1,400°C. The good results are because of the enhancement of the density by liquid sintering at the lower temperatures. With the mixtures of V 2 O 5 and Li 2 CO 3 , the sintering temperature of MN was further reduced to 925°C at the expense of the quality factor (Q · ƒ) value. Typically, e of 13.7 and Q · ƒ value of 78,000 GHz were obtained for the specimens with mixtures of 1.5wt% V 2 O 5 and 1.5wt% Li 2 CO 3 and sintered at 925°C for 5 h.

Low-temperature synthesis of Mg4Nb2O9 nanopowders by high-energy ball-milling method

“…For preparing single-phase Pb(Mg 1/3 Nb 2/3 )O 3 [3,4], MN shows better character than MgNb 2 O 6 [5,6]. Much attention has been paid to the fabrication of MN single crystal [7], luminescent properties and microwave dielectric properties of MN ceramic [1,2,8,9]. Usually, MN powders are synthesized by the conventional ball-milling method [10][11][12].…”

Phase Compositions and Microwave Dielectric Properties of Na1+xSrB5O9+0.5x Ceramics

“…Of these, borate ceramics have received substantial attention in recent years owing to their low raw prices, variable chemical structures, excellent dielectric properties, and straightforward preparation processes. Liu et al [12] reported that LiMBO 3 (M = Ca, Sr) ceramics could be densified at 800 • C with excellent dielectric properties (ε r = 8.7, Q × f = 75,000 GHz, and τ f = −150 ppm/ • C and ε r = 8.6, Q × f = 60,000 GHz, and τ f = −39 ppm/ • C) and could be chemically compatible with Ag. Zhou et al [13] prepared dense Li 6 B 4 O 9 microwave dielectric ceramics at 640 properties of ε r = 5.95, Q × f = 41,800 GHz, and τ f = −72 ppm/ • C, and a prototype patch antenna was fabricated by exploiting the compatibility of Li 6 B 4 O 9 with silver metallization using LTCC technology.…”

Sinterability and Microwave Dielectric Properties of Li₂CO₃-V₂O₅ Added Mg₄Nb₂O₉-CaTiO₃ Composite Ceramics

“…A combination of Li 2 CO 3 and V 2 O 5 has been reported as a good fiux former to lower the sintering temperature for many materials [8,9]. The authors reported that the 3.0wt% Li 2 CO 3 -V 2 O 5 doped Mg 4 Nb 2 O 9 ceramic could be well sintered at 925 o C, while maintaining good dielectric properties [10]. Therefore, the effects of Li 2 CO 3 -V 2 O 5 combination addition as a sintering aids on the sintering behavior, microstructure and microwave dielectric properties of Mg 4 Nb 2 O 9 -CaTiO 3 composite ceramics were investigated.…”