New Li3Ni2NbO6 microwave dielectric ceramics with the orthorhombic structure for LTCC applications

New Li3Ni2NbO6 (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. NbO 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 εr = 15.85, Q·ƒ = 19,860 GHz and τf = −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. [Display omitted] •New low-temperature sintering Li3Ni2NbO6 ceramics were prepared.•Rietveld refinement was used and lattice parameters were obtained.•Bond ionicity, lattice energy and bond energy were calculated.•Infrared reflectivity spectrum was used to analyze the vibrational phonon modes.