Preparation and characterization of ZrB2-TiB2 based composites for hypersonic systems

Abstract

ZrB2 ceramics are considered potential materials for hypersonic systems in view of the melting point exceeding 3000 °C and excellent ablation resistance. Second phases, including SiC or CrB2, further improve the oxidation behavior, whereas a lighter phase, like TiB2 can decrease the overall weight. In this work, a powder mixture containing ZrB2, TiB2, CrB2 and SiC was mechanically activated using high energy ball-milling. Sintering was performed by hot pressing following different thermal cycles, and subsequent annealing to remove oxide phases and reduce micro-cracking. The microstructure and hardness of the dense ceramics are compared in relationship to the thermal history. Fully dense ceramics were obtained with different oxide-phases amount depending on the sintering cycle and hardness approaching 24 GPa were achieved. Future works will explore the strength and oxidation resistance of this multi-phase system to check its suitability for hypersonic systems.