Thermodynamic properties of aluminum titanate-mullite composite ceramics containing heat stabilizer

Using Al₂O₃ and TiO₂ as raw materials, adding MgO as heat stabilizer and mullite as enhancer, aluminum titanate-mullite multiphase ceramics were successfully prepared by solid phase synthesis. The effects of MgO and mullite were systematically studied on the phase composition, microstructure, thermal stability, sintering properties, and mechanical properties of aluminum titanate ceramics. The results showed that the introduction of Mg²⁺ can partially replace Al³⁺ to form Mg_xAl_2(1-x)Ti_(1+x)O₅ solid solution, improved the thermal stability of aluminum titanate ceramics, and promoted the formation and growth of grains, which reduced the sintering temperature. The crack deflections caused by mullite particles improved the mechanical properties. The filling effect of mullite particles and the formation of silica in mullite raw materials were conducive to ceramic densification. The statistics of Mg4M10 sample were as follows: the porosity was only 2.9%, the flexural strength was as high as 64.15 MPa, and the thermal expansion coefficient was 1.35 × 10⁻⁶ K⁻¹ (RT-700°C), encouraging the application of ceramics with high thermal mechanical properties.