Low-temperature fabrication of thermomechanically enhanced aluminum titanate ceramics using silicon nitride as a sintering aid
摘要
In this study, aluminum titanate (Al2TiO5) was synthesized via the solid-state reaction method using the Al2O3-TiO2 system as raw materials with Si3N4 employed as a sintering aid. The effects of the additive on the phase composition, microstructure, sintering behavior, and thermomechanical properties of the material were investigated. The experimental results indicate that the use of an optimal amount of additive facilitates the formation of the aluminum titanate ceramic matrix. The microstructure was characterized by a microcracked matrix and interlocked grains. The beneficial SiO2 liquid phase, generated by the addition of Si3N4, was found to wet grain boundaries, promote particle rearrangement and mass transport, fill interparticle pores, and accelerate densification. Consequently, samples incorporating Si3N4 exhibited both excellent densification performance and refined microstructure. Furthermore, a flexural strength of 72.73 MPa and a coefficient of thermal expansion as low as 0.424 × 10-6 K-1 (measured from 30 to 1200 °C) were attained for the sample sintered at 1450 °C. These properties demonstrate significant potential for refractory applications requiring high thermomechanical performance.