Enhanced flexural strength and microwave dielectric properties of Li2MgTi3O8-based low temperature co-fired ceramics

Abstract

With the rapid development of 6G wireless communication, research on highly integrated and multifunctional miniature electronic components has gained significant attention. Li₂MgTi₃O₈ (LMT) ceramics are excellent microwave dielectric materials. However, their high sintering temperature and low flexural strength limit their application in LTCC devices. Therefore, in this study, TiN-doped LMT ceramics were prepared using a traditional solid-state reaction method, and the effects of TiN addition on the LMT ceramics were investigated. The best performance of Q × f = 67 275 GHz, τ_f = −6.02 ppm °C⁻¹, ε_r = 24.53, and σ_f = 174.7 MPa was obtained for LMT ceramics doped with 0.2 wt% TiN sintered at 1025 °C. The addition of 1 wt% LiF and 1 wt% MgO to LMT + 0.3 wt% TiN (LMT-NFM) ceramics reduced the sintering temperature, increased the density, and enhanced the flexural strength of the ceramics. When the sintering temperature was 850 °C, the material exhibited the best performances with Q × f = 53 477 GHz (at 7.48 GHz), τ_f = −9.50 ppm °C⁻¹, ε_r = 24.94, and σ_f = 200.98 MPa. The LMT-NFM ceramic could coexist with the Ag electrode, indicating that it is a promising material for manufacturing ceramic multilayer packaging substrates and various functional components.