Preparation and properties of 0.79ZnAl2O4-0.21TiO2 microwave dielectric ceramics via digital light processing

Abstract

0.79ZnAl 2 O 4 -0.21TiO 2 microwave dielectric ceramics are ideal materials for preparing 5 G lens antennas. However, conventional processing methods are difficult to meet the requirements of microwave devices for high precision and designed complicated structures. Additive manufacturing technologies provide opportunities for the fabrication of these devices. Herein, we fabricated 0.79ZnAl 2 O 4 -0.21TiO 2 ceramics by digital light processing (DLP). The slurry with 2 wt% dispersant content showed favorable dispersion effect and stability. The optimal penetration depth of 44.64 µm and critical energy dose of 3.04 mJ/cm 2 were obtained. After sintering , the 0.79ZnAl 2 O 4 -0.21TiO 2 ceramic only kept ZnAl 2 O 4 phase and TiO 2 phase. The relative density could reach 95.29%, which is comparable to that of dry-pressed sample. With the increase of sintering temperature , dielectric constant ( ε r ) and quality factor ( Q×f ) of 0.79ZnAl 2 O 4 -0.21TiO 2 ceramic increased first and then decreased. The sintered ceramic at 1550 °C exhibited excellent microwave dielectric properties ( ε r = 11.55, Q×f = 62,266 GHz, τ f = −0.64 ppm/°C). The results indicate that DLP is a promising technology to fabricate high-performance microwave dielectric ceramics with complex structures. • High-performance 0.79ZnAl 2 O 4 -0.21TiO 2 ceramics were fabricated by DLP technology. • The sintered ceramic only kept ZnAl 2 O 4 spinel phase and TiO 2 rutile phase. • The relative density (95.29%) could be comparable to that of dry-pressed sample. • The ceramic showed excellent microwave dielectric property ( ε r = 11.55, Q×f = 62,266 GHz).