The mechanical and dielectric properties of high-density Ti-doped MgAl2O4 ceramic prepared by non-hydrolytic sol-gel combined with mechanochemical method

The synthesis of MgAl₂O₄ requires high calcination temperatures which generally result in larger grain sizes and smaller specific surface areas. These factors pose challenges in achieving high-density MgAl₂O₄ ceramic. This study introduces an innovative approach that has successfully sintered MgAl₂O₄ ceramic at 1500 ℃ with MgAl₂O₄ powder prepared using a Non-Hydrolytic Sol-Gel (NHSG) method combined with a mechanochemical method. The sintered MgAl₂O₄ ceramic with 2 wt% TiCl₄ doping displays an apparent porosity of only 0.09 %, a flexural strength of 183 MPa, a relative permittivity of 8.7, a quality factor of 77000 GHz, and a frequency temperature coefficient of −59.4 ppm/℃. The introduction of titanium ions causes lattice distortion and cationic vacancies, which promotes sintering and improves the mechanical and dielectric properties of the resulting ceramic. This study demonstrates the effectiveness of NHSG combined with the mechanochemical method in preparing MgAl₂O₄ ceramic with enhanced sintering properties.