Porous ZrC/C targets for radioactive ion beam production synthesized via in-situ carbothermal reduction of pressed and mould-casted pellets

Porous ZrC/C ceramics were developed for Isotope Separation On-Line (ISOL) facilities through in-situ carbothermal reduction of ZrO₂ with graphite or carbon black. Conventional pressing and mould casting with 30 vol% polyamide pore formers were used for green pellet fabrication, with ZrO₂/C molar ratios of 1:4 or 1:5. Pressureless SPS at 2000 °C enabled synthesis of porous ZrC/graphite targets with tailored microstructure. Complete carbothermal reduction was achieved with low oxygen content (<1.5 wt%) and ZrC_x was produced. Mould-casted pellets exhibited higher open porosity up to 61% with a multimodal pore size distribution, whereas pressed pellets had a bimodal pore network. The ZrC grain size of 2–5 µm was well below the limit for efficient isotope release. High-temperature testing at 1800 °C for 15 h in high vacuum demonstrated structural integrity and limited microstructural degradation, with excess graphite hindering densification.