A New Niobate Ba 6 LaTi 3 Nb 3 O 21 was synthesized by high temperature solid state reaction in the BaO - La 2 O 3 - TiO 2 - Nb 2 O 5 system.The chemical compositions,crystal structure,microstructure,density and melti...A New Niobate Ba 6 LaTi 3 Nb 3 O 21 was synthesized by high temperature solid state reaction in the BaO - La 2 O 3 - TiO 2 - Nb 2 O 5 system.The chemical compositions,crystal structure,microstructure,density and melting point of the new compound were characterized by EPMA,XRD,DTA and so on.Ba 6 LaTi 3 Nb 3 O 21 crystallizes the rhombohedral system with unit cell parameters a=0.57388(2)nm,c=4.9283(3)nm,and space group R3m,Z=3.The structure may be described as six(Nb,Ti)O 6 octahedra corner - sharing along c - axis to form perovskite layer connected by Ba atoms.The Ba 6 LaTi 3 Nb 3 O 21 ceramics exhibits high dielectric of74.1,low dielectric loss of4.7 × 10 -4 and small temperature coefficient of dielectric constant of-69ppm · K -1 at1MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+ ,La 3+ ,Ti 4+ and Nb 5+ .Ba 6 LaTi 3 Nb 3 O 21 might be a suitable candidate of highε r mi - crowave dielectric ceramics.展开更多
For low temperature co-fired ceramics (LTCC) materials, a glass-ceramic composite consisting of a BaNd2Ti5O14 ceramic, and a lead-free rare earth derived boron glasses (LBT) was tested in this present study. The glass...For low temperature co-fired ceramics (LTCC) materials, a glass-ceramic composite consisting of a BaNd2Ti5O14 ceramic, and a lead-free rare earth derived boron glasses (LBT) was tested in this present study. The glass-ceramic composite was evaluated for relative densities, shrinkage and microwave dielectric properties (εr, Qxf0). The sintered body at low temperature demonstrated applicable properties such as high relative density over 85% and various dielectric properties,namely 13-20 for εr, 2000-10000 GHz for Qxf0. The results suggest that the composite has a good potential for using low temperature co-fired ceramic compositions for high-frequency application.展开更多
文摘A New Niobate Ba 6 LaTi 3 Nb 3 O 21 was synthesized by high temperature solid state reaction in the BaO - La 2 O 3 - TiO 2 - Nb 2 O 5 system.The chemical compositions,crystal structure,microstructure,density and melting point of the new compound were characterized by EPMA,XRD,DTA and so on.Ba 6 LaTi 3 Nb 3 O 21 crystallizes the rhombohedral system with unit cell parameters a=0.57388(2)nm,c=4.9283(3)nm,and space group R3m,Z=3.The structure may be described as six(Nb,Ti)O 6 octahedra corner - sharing along c - axis to form perovskite layer connected by Ba atoms.The Ba 6 LaTi 3 Nb 3 O 21 ceramics exhibits high dielectric of74.1,low dielectric loss of4.7 × 10 -4 and small temperature coefficient of dielectric constant of-69ppm · K -1 at1MHz due to its close structure and relative high dielectric polarizabilities of Ba 2+ ,La 3+ ,Ti 4+ and Nb 5+ .Ba 6 LaTi 3 Nb 3 O 21 might be a suitable candidate of highε r mi - crowave dielectric ceramics.
文摘For low temperature co-fired ceramics (LTCC) materials, a glass-ceramic composite consisting of a BaNd2Ti5O14 ceramic, and a lead-free rare earth derived boron glasses (LBT) was tested in this present study. The glass-ceramic composite was evaluated for relative densities, shrinkage and microwave dielectric properties (εr, Qxf0). The sintered body at low temperature demonstrated applicable properties such as high relative density over 85% and various dielectric properties,namely 13-20 for εr, 2000-10000 GHz for Qxf0. The results suggest that the composite has a good potential for using low temperature co-fired ceramic compositions for high-frequency application.
