Microwave dielectric properties of Mg4Nb2O9–3.0wt.% LiF ceramics prepared with CaTiO3 additions

Low-temperature sintering and microwave dielectric properties of Mg4Nb2O9 ceramics

“…The e of 13.7, Q · ƒ value of 78,000 GHz were obtained for the specimens with 1.5wt% V 2 O 5 and 1.5wt% Li 2 CO 3 sintered at 925°C. The excellent microwave dielectric properties and lowtemperature sintering characteristics of V-and Li-bearing MN ceramics permit the potentional applications as a novel LTCC substrate, which is in agreement with the LiF-doped results [6,13].…”

Fabrication, phase formation and microstructure of Ni4Nb2O9 ceramics fabricated by using the two-stage sintering technique

“…Its crystal structure can be represented as a network of edge-and corner-sharing NiO 6 and NbO 6 octahedra dimmers [1][2][3]. This material is a potential candidate for the development of dielectric ceramic resonators used at microwave frequencies especially for mobile communication and satellite systems [4][5][6]. Recently, Liou et al prepared Ni 4 Nb 2 O 9 ceramics by the reaction-sintering process where a mixture of NiO and Nb 2 O 5 precursors were directly sintered into Ni 4 Nb 2 O 9 ceramics by bypassing calcination step.…”

“…However, they found that minor NiO and NiNb 2 O 6 phases tended to form together with the Ni 4 Nb 2 O 9 phase, depending on sintering condition [7,8]. Thus, there has been a great deal of interest in the preparation of single-phase Ni 4 Nb 2 O 9 ceramic. In addition, the Ni 4 Nb 2 O 9 phase is very unstable, compared to the second phase that can easily be formed during preparation [7,8].…”

Microwave dielectric properties of Re3Ga5O12 (Re: Nd, Sm, Eu, Dy and Yb) ceramics and effect of TiO2 on the microwave dielectric properties of Sm3Ga5O12 ceramics

“…In the case of Al 2 O 3 , rutile (TiO 2 ) was added to address this problem, and the resulting 0.9Al 2 O 3 -0.1TiO 2 ceramics were reported to have good microwave dielectric properties of ε r = 12.4, Q × f = 117,000 GHz and τ f = 1.5 ppm/ • C. 8 In the case of Mg 4 Nb 2 O 9 ceramics with 3.0 wt% LiF, CaTiO 3 was additionally added to the system. 9 However, although a zero τ f value was obtained, the other properties were not desirable. TiO 2 was also added to Mg 2 SiO 4 ceramics in order to enhance the τ f value and lower the sintering temperature.…”