Mullite whisker network reinforced ceramic with high strength and lightweight

High strength lightweight mullite whisker network reinforced ceramic materials was successfully prepared by firing a bauxite - kaolin - coal fly ash mixture with additions of varying mixtures of feldspar - talcum - BaCO₃- pyrolusite. The mullite whisker network exhibits a unique architecture in which thin mullite crystals layers with anisotropic properties and well controlled crystal size were interweaved with one another. The effects of pyrolusite content on morphologies and properties of resultant ceramic materials were investigated. The phase compositions and microstructures of several samples were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The flexural strength and acid solubility of ceramic materials as functions of sintering temperature were systematically investigated by measuring the flexural strength and acid solubility at different sintering temperature, respectively. The resulting mullite whisker network structure ceramic materials showed optimum performance at sintering temperature around 1390 °C when the content of pyrolusite equals to 6 wt%, such as high strength (190.10 MPa), low density (1.48 g cm⁻³) and low acid solubility (2.55 wt%). The approach opens new opportunities for the sintered ceramic as a proppant material since the ceramic system displays low acid solubility and good flexural strength.