Photopolymerization and reaction sintering of ZrC/SiC ultra-high-temperature ceramics fabricated by 3D printing

Zr-based ultra-high temperature ceramics (UHTCs) are widely used as the key parts of aircrafts in thermal protection systems. However, such materials usually have a high sintering temperature and it is difficult to obtain complex parts using traditional manufacturing methods. This study reports on the success preparation of complex Zr-based UHTCs by a light-curing 3D printing process. The results indicate that the smaller the precursor particle size, the higher is the viscosity of the slurry used for printing. Slurries with a better curing performance can be prepared by mixing various active diluents and photoinitiators with an optimized certain proportion. The stability of the slurry can be improved by adding coupling agents and dispersants. The main components of the 3D printed green parts are ZrC, SiC and pyrolytic carbon at 1800 °C, yielding a high compressive strength (102 ± 2 MPa) and elastic modulus (65 ± 1 GPa). ZrC/SiC composite ceramic parts with low open porosity (3.99 %) were obtained by 3D printing after heat treatment, which provides an effective way to design complex UHTC parts for extreme environment applications.