Ultrafast high-temperature sintering and densification of ZrC-based ceramics

Zirconium carbide (ZrC) ceramics are promising candidates for high-temperature structural components and nuclear reactors. However, their poor sinterability has limited widespread application. This study explored the sintering and densification of ZrC-based ceramics with graphite or B4C additive using ultrafast high-temperature sintering (UHS). A nearly fully dense ZrC ceramic (> 98%) could be obtained by adding 2.5 wt% B4C additive via ultrafast high-temperature sintering at 2300 °C within 3 min. Additionally, the results revealed that adding graphite into ZrC was beneficial to reduce the grain size but detrimental to densification. Compared to ZrC ceramics sintered using conventional pressureless sintering (PLS) at 2400 °C for 60 min, ZrC-based ceramics with 2.5 wt% B4C sintered via UHS at 2400 °C for 30 s exhibited higher relative densities, smaller grain sizes, and greater Vickers hardness due to faster heating rates and shorter sintering processes.