Microstructure and microwave dielectric properties of Ni doped zinc borate ceramics for LTCC applications.

A detailed study was performed using the density function theory to research the mechanism of the improvement of the sintering and dielectric properties of Ni2+ substituted Zn 3 B 2 O 6 ceramic. The mechanism involved bond properties, electron density and formation energy. The synthesis process is based on the solid-state reaction method and characterized via scanning electron microscopy, X-ray energy-dispersive spectroscopy, Raman spectrometry, network analysis, differential thermal analysis and thermo-mechanical analysis. The Zn1 site was the priority to be substituted by Ni2+, and the substitution happened in all the Zn tetrahedrons. The activation energy and densification window decreased slightly, and the sintering property was modified. The bond property and electron distribution around the tetrahedron with Ni2+ changed, and densification level and dielectric performance of the ZBO ceramic improved (ε r = 6.9, Q × f = 91,000 GHz at 15 GHz, τ f = −55.6 ppm/°C with high relative density (97.1%) at 900 °C). • The first principle calculation was performed to research the mechanism of the improvement of the sintering and dielectric properties of Zn 3 B 2 O 6 ceramic with Ni2+ substitution. The mechanism involved bond properties, electron density and formation energy. • The Zn1 site was the priority to be occupied by Ni2+, and the substitution happened in all the Zn tetrahedrons. The activation energy and densification window decreased slightly, and the sintering property was modified. The bond property and electron distribution of Zn tetrahedron changed. • Densification level and dielectric properties of the ZBO ceramic improved (ε r = 6.9, Q × f = 91,000 GHz at 15 GHz, τ f = −55.6 ppm/°C and relative density=97.1% at 900 °C). [ABSTRACT FROM AUTHOR]