Ultrafast pressure sintering of B4C-based composites via direct Joule heating

Traditional sintering of B4C-based ceramics typically requires high temperatures (≥ 2000 °C), long isothermal durations (15–30 min), and high pressures (20–30 MPa), and hence, energy consumption is significant. Here, we propose an ultrafast pressure sintering technique involving direct Joule heating of graphite felt for the low-temperature (1550 °C) and rapid (≤ 2 min) densification of B4C-based ceramics. The effects of temperature, pressure, and sintering aid (TiSi2) content on the relative density of B4C were investigated. The high densification achieved is attributed to an in situ reaction and pressure-guided particle rearrangement induced by the formation of a transient TiSi2-Si eutectic liquid phase. In particular, TiB2 and SiC formed by the addition of TiSi2 significantly increased the fracture toughness of B4C. This study provides a novel, efficient, and energy-saving method for the rapid and scalable preparation of bulk ceramics.