Electromagnetism and thermostability of Cr7C3 synthesised with high-temperature and high-pressure quenching method

The interactions between the carbon skeleton and metal atoms in binary transition metal carbides are of particular interest for industrial applications involving advanced physics and chemistry, especially in magnetoelectric functional materials and cemented carbides. Cr and carbon BTMCs are a series of intermetallic compounds with specific chemical formulas that share certain unique characteristics. In this study, we used polycrystalline powders of chromium and carbon as precursors and synthesised single-phase bulk Cr7C3 (orthorhombic, space group: Pnma) with high density and good crystallinity using a high-temperature and high-pressure quenching method (HTHPQM). We studied the material properties and electronic structures of Cr7C3 with both experimental measurements and density functional theory ab intio simulations and found that Cr7C3 is a conductor with an electrical conductivity (2.32 × 10−3 Ω m), relatively high compaction (97.2%), excellent thermostability (oxidation at 1175 K), and a magnetic phase transition from paramagnetism to soft ferromagnetism around 50 K, and the electromagnetic properties are chiefly due to the abundance of the 3d electrons of Cr, and the orbital hybridisation between C and Cr with their 2p and 3d electrons is the reason for the crystal structure and high thermostability. Therefore, the synthesised Cr7C3 is a multifunctional material with promising application prospects, and HPHTQM is a simple and effective method for preparing samples.