采用一次烧成工艺制备了 Ni O、Cu O掺杂的 Sr Ti O3复合功能陶瓷 ,研究了其烧成状况、显微结构、复合功能特性及小电流区的电流 -温度关系。研究结果表明 ,掺 Ni O样品的晶粒粒度明显大于掺 Cu O样品 ;由于在烧成过程中受主杂质的行为有所不同 ,掺 Cu O样品具有较高的晶界受主态浓度。这使得在制备条件和掺杂浓度相同的条件下 ,掺 Ni O样品和掺 Cu
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.
