Improved crystalline structure and sintering characteristics of nonstoichiometric MgTiO₃ ceramics by sol–gel method

In this work, nonstoichiometric MgTiO₃ ceramics were prepared by the sol–gel method. The crystalline structure, morphology, and microwave dielectric properties of the MgTi_0.98O_2.96 ceramics were investigated in detail. Compared to the samples prepared by the solid state method, the nonstoichiometric ceramics also had a high-density (~94.33% of the theoretical density) and high-quality factor (Q × f of 46,400 GHz). Meanwhile, the sintering characteristic was dramatically improved, making the densification sintering temperature reduce by 300 °C, from 1420 to 1120 °C. The lower temperature densification sintering can be ascribed to the high activity of the ceramic powders from the sol–gel process, the distortion of the octahedron, and the volume reduction of the unit cell. This study indicates that the sol–gel method is a promising way to prepare microwave materials, which can be applied in the efficient transmission of 5G wireless networks.