Effects of Nd2O3 and TiO2 Addition on the Microstructures and Microwave Dielectric Properties of BaO-Nd2O3-TiO2 System

ABSTRACT The effects of Nd 2 O 3 and TiO 2 additionon the microstructures and microwavedielectic properties of BaO-Nd 2 O 3 -TiO 2 system were investigated. BaNd 2 Ti 4 O 12 or BaNd 2 Ti 5 O 14 phases were observed forcompositions based on BaO/Nd 2 O 3 D1ratio. The compositions deviated fromBaO/Nd 2 O 3 D1 ratio were composedof major phases of BaNd 2 Ti 4 O 12 orBaNd 2 Ti 5 O 14 , and the compound ofNd 2 O 3 and TiO 2 (Nd 2 Ti 2 O 7 )orthatofBaOand TiO 2 (BaTi 4 O 9 ). The microstructureof ceramic with BaONd 2 O 3 4TiO 2 com-position varied from spherical grains toneedlelike grains with increasing sinteringtemperature. With increasing Nd 2 O 3 ,the optimum sintering temperature withmaximum density increased, and the di-electric constant(" r ) and quality factor(Q)decreased due to the formation of sec-ondary phases. With increasing TiO 2 ,theoptimum sintering temperature and the di-electric constant decreased with increasedQ value. And the temperature coefficientof resonant frequency, ˝