Microstructure and properties of nano-laminated Y₃Si₂C₂ ceramics fabricated via in situ reaction by spark plasma sintering

A nano-laminated Y₃Si₂C₂ ceramic material was successfully synthesized via an in situ reaction between YH₂ and SiC using spark plasma sintering technology. A MAX phase-like ternary layered structure of Y₃Si₂C₂ was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping were observed at the tip of the Vickers indents. The elastic modulus and Vickers hardness of Y₃Si₂C₂ ceramics (with 5.5 wt% Y₂O₃) sintered at 1500 ℃ were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W·m^-1·K^-1 and 6.3×10⁵ S·m^-1, respectively.