Pr₃Si₂C₂ is a ternary layered structural material, which combines the merits of ceramics and metals. The synthesis of Pr₃Si₂C₂ is a critical issue for its applications, since the highly reactive Pr is easily oxidized. The Pr₃Si₂C₂ powder was synthesized using a molten salt method through the in-situ reaction between Pr and SiC. Mixed NaCl-KCl molten salt with a molar ratio of 1:1 was used to supply the liquid phase reaction medium and promote the matter transportation. The effects of the molten salt temperature on phase composition and microstructure of the as-obtained Pr₃Si₂C₂ powder were studied. The results indicated that the Pr₃Si₂C₂ powder with a ~8 wt.% oxygen can be obtained at the molten salt temperature of 850 ℃ for 5 h in Ar. The proposed molten salt method for the synthesis of Pr₃Si₂C₂ powder can be potentially used for the fabrication of Pr₃Si₂C₂ ceramics and sintering additive of SiC ceramics and SiC matrix ceramic composites.

Low temperature sintering of highly dense SiC ceramics is one of the research focuses of scholars in industries, because of the high degree of Si-C covalent bonding and the low self-diffusion coefficient of SiC. Noting that low-temperature eutectic liquid phase transition between Pr₃Si₂C₂ and SiC can promote the sintering of SiC, Pr₃Si₂C₂ was grown in-situ on the surface of SiC particles by using a molten salt method, in order to ensure the uniform dispersion of Pr₃Si₂C₂ in the SiC particles. SiC ceramics with high density (porosity of 0.3%) and thermal conductivity of up to 106 W·m^-1·K^-1 were successfully fabricated, by using electric current field-assisted sintering technology at a low temperature of 1500 ℃. According to microstructure of the SiC ceramics, it is concluded that the sintering process followed a typical solution-precipitated liquid phase sintering mechanism. Therefore, Pr₃Si₂C₂ is a promising low-temperature sintering additive for the low-temperature sintering of SiC ceramics and their composites.

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.