Effect of Ni substituted ZnZrTa2O8 ceramics on crystal structure and microwave dielectric properties

Zn 1− x Ni x ZrTa 2 O 8 ( x  = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) microwave dielectric ceramics were synthesized by traditional solid-state method. The effect of introducing Ni–O bonds to replace part of Zn–O bonds on the ceramic lattice and microwave dielectric properties was systematically studied. An appropriate amount of Ni 2+ substitution improves the microscopic morphology of crystal, including the grain size, number of pores, number of grain boundaries, and the grain uniformity, giving rise to an increase in the compactness of ceramics and, thereby enhancing the microwave dielectric properties. The Raman analysis prove that the introduction of Ni 2+ is beneficial to enhance the vibrational peak intensity of the oxygen octahedron and effectively improve the Q × f value. However, the introduction of excessive Ni 2+ will lead to the decrease of lattice oxygen and the increase of adsorbed oxygen, and the crystal will become relatively active and unstable, and the microwave performance will decrease. In addition, the substitution of Ni 2+ can also effectively control the resonance temperature coefficient, which is beneficial to improve the τ f value. As a result, Zn 0.94 Ni 0.06 ZrTa 2 O 8 exhibits excellent microwave dielectric properties: ε r  = 32.15, Q × f  = 15,7500 GHz, τ f  = − 33.1 ppm/°C, presenting as a potential candidate for low-loss microwave dielectric materials.