Enhanced bending strength and microwave dielectric properties of Li2MgTi3O8 ceramics by adding Si3N4 reinforcing phase

In the 5G era, the dielectric materials used in microwave electronic components must have not only have good microwave dielectric characteristics but also excellent structural characteristics. Li₂MgTi₃O₈ (LMT) ceramics have excellent microwave dielectric properties; however, their low bending strength limits their further applications in the 5G era. In this work, the dielectric properties and bending strength of LMT ceramics were optimized by the addition of Si₃N₄ reinforcing phase using a solid-phase method, and the effects of Si₃N₄ addition on the sintering properties, microscopic structure, crystalline phase, dielectric properties and bending strength of ceramics were investigated. The X-ray diffraction pattern indicates that all ceramics exhibit spinel structure. Combined with the phenomenon of grain reduction in the SEM graph, it indicates that the addition of Si₃N₄ can inhibit the grain growth and achieve the purpose of fine-grain strengthening. The dispersion enhancement of second phase particles is also one of the reasons for the increase of bending strength. LMT ceramics doped with 0.5 wt% Si₃N₄ exhibited the maximum bending strength after sintering at 1050 °C for 4 h, which was 76.97% higher than that of pure LMT ceramics. In addition, the ceramics exhibited outstanding dielectric properties: a dielectric constant of 23.20, quality factor of 49344 GHz, and temperature coefficient of ?5.90 ppm/°C. The high bending strength and good microwave dielectric properties indicate that Si₃N₄-added LMT ceramics can be effectively applied in the 5G era.