Preparation of nanocrystalline ultra-high temperature Ta4ZrC5 ceramics by joint processes of solvothermal and carbothermal reaction

An attractive way to prepare nanocrystalline tantalum zirconium carbide ternary ceramics was proposed and confirmed experimentally. The experimental results showed the Ta4ZrC5 powders were successfully fabricated by joint processes of solvothermal and carbothermal reaction. The thermodynamic change process in the Ta2O5-ZrO2-C system was studied. The reactions were substantially completed at relatively lower temperatures (∼1873 K/1 h) and the synthesized powders had a small average crystallite size (∼10 nm). The crystalline structure and the nitrogen sorption isotherms patterns of the product were studied. Besides, a monolithic Ta4ZrC5 ceramics was densified without sintering additives by pressureless sintering.