LAUSR

Abstract New Li 3 Ni 2 NbO 6 (indexed as LNN) microwave dielectric ceramics were prepared by the conventional solid-state method. The phase composition, crystal structure, sintering characteristics, micro-structures, microwave dielectric properties, intrinsic factors and vibrational phonon modes were investigated. XRD results showed that LNN phase exhibit orthorhombic structure with Fddd (No. 70) space group. Rietveld refinement was applied to analyze the crystalline structure and the lattice parameters were obtained. On the basis of the chemical bond theory and lattice parameters, the bond ionicity, lattice energy, bond energy and coefficient of thermal expansion were calculated to evaluate the structural characteristics. Nb O bonds played an important role in affecting the microwave dielectric proprieties of LNN ceramics. The results of Infrared reflectivity spectrum indicated that the absorptions of phonon oscillation played an important influence on the dielectric contribution of LNN ceramics. At the sintering temperature of 850 °C, excellent microwave dielectric properties of e r  = 15.85, Q·ƒ  = 19,860 GHz and τ f  = −15.45 ppm/°C were obtained for LNN ceramics. The excellent microwave dielectric properties and low sintering temperature of LNN ceramics made it a promising candidate for low temperature co-fired ceramics (indexed as LTCC) applications.