China claims super ceramics for nuclear reactors, hypersonic jets

Chinese researchers at Harbin University have developed ultra-high-temperature ceramics (UHTCs) capable of withstanding temperatures up to 3272°F (1800°C), targeting applications in hypersonic jets and next-generation nuclear reactors. Utilizing a novel two-step in-situ reactive spark plasma sintering (SPS) process with raw materials zirconium carbide (ZrC), titanium disilicide (TiSi2), and boron carbide (B4C), the team overcame longstanding challenges related to ZrC’s poor sinterability and brittleness. The first sintering step at 1600°C promotes reactions forming TiB2 and SiC, while the second step at 1800°C facilitates further reactions producing ZrSi2, secondary SiC, and solid solutions (Zr,Ti)C and (Ti,Zr)B2. This sequence results in a hierarchical microstructure with reinforcing phases at multiple scales, enhancing mechanical properties. The resulting ZrC-based multiph