In situ synthesis of high porosity ZrB₂ ceramics using organic-inorganic hybrid precursors

We designed a novel organic-inorganic hybrid precursor for the synthesis of pure phase ZrB₂ porous ceramics. Resorcinol, formaldehyde, zirconium oxychloride, and boric acid were used as raw materials. A binary solvent composed of water and DMF was employed to enhance the solubility of boric acid at room temperature. The organic framework formed by the polymerization of resorcinol and formaldehyde effectively binds with the inorganic network through hydrogen bondings. This structure can withstand the capillary forces generated by solvent evaporation during the ambient pressure drying process while simultaneously lowering the temperature required for the boron/carbon thermoreduction reaction. The prepared ZrB₂ porous ceramics exhibit low density (329 mg/cm³), excellent compressive strength (1.41 MPa) and corresponding high porosity (88.37 %), as well as high light absorption efficiency in the wavelength range of 400–2000 nm (96.53 %). The prepared ZrB₂ porous ceramics demonstrate broad application prospects in the field of light absorption.