Mullite fiber cloth-reinforced mullite composite fabricated via an optimized layer-by-layer assembly method

This article reports the fabrication of fiber cloth-reinforced mullite composite via an optimized layer-by-layer (LbL) assembly method involving the infiltration and pyrolysis of fiber cloth with mullite precursor (PIP) followed by brushing matrix onto the treated fiber cloth and hot pressing. The influence of fiber content on the microstructure and mechanical properties of composite are investigated and the crack propagation is discussed to explain the toughening mechanisms. The composite with 30 vol% fiber content exhibited a high density 2.89 g/cm³, flexural strength 135.5 MPa and fracture toughness 4.13 MPa m^1/2. After PIP pretreatment, the gaps existed in the fiber bundle are filled with mullite matrix which transform from mullite precursor, improving the density from 2.89 g/cm³ to 2.94 g/cm³, flexural strength from 135.5 MPa to 163.2 MPa and fracture toughness from 4.13 MPa m^1/2 to 4.55 MPa m^1/2. The optimized LbL assembly method realizes the creation of fiber cloth-reinforced mullite composites with high density and excellent mechanical properties.