Fabrication and mechanical properties of layered ceramic based on mullite platelets prepared via molten salt method

In this study, mullite platelets were successfully synthesized via molten salt method for fabrication of layered mullite ceramic. The effects of calcination temperature on the morphology and composition of the powder were investigated. With the temperature increase, the powder morphology transformed from irregular to flaky, ultimately resulting in the formation of mullite platelets with uniform particle size at 1000 °C. The growth mechanism of mullite platelets was discussed in details. Incorporating these mullite platelets as components in the fabrication of layered mullite ceramic resulted in high flexural strength and toughness (337.2 ± 24.3 MPa and 5.66 ± 1.3 MP m^1/2). The layered structure improved the fracture toughness of mullite ceramic through mechanisms such as crack deflection, branching, mullite platelet rotation and bridging. The findings of this study would provide valuable insights and guidance for the fabrication of mullite ceramic with high strength and toughness.