Molten salt synthesis of orthorhombic CrB and Cr2AlB2 ceramics

High-purity and fine CrB powders are firstly synthesized from Cr and B powders in (Na, K)Cl molten salt at 850 degrees C for 2 h. Then the as-achieved CrB powders are used as precursors to synthesize homogeneous and size-controlled Cr2AlB2 powders in (Na, K)Cl molten salt at 900 degrees C for 2 h. Additionally, the formation mechanisms of CrB and Cr2AlB2 in (Na, K)Cl molten salt are also investigated. Results show that the Cr atom, formed by disproportionation of Cr2+ ions in molten salt, reacts in-situ with B powders to form CrB. For the formation of Cr2AlB2, Al and CrB migrate mutually and assemble firstly in the molten salt, and then Al intercalates into CrB to generate Cr2AlB2.

Automated summary

High-purity and fine CrB powders were synthesized in (Na, K)Cl molten salt at 850 degrees C for 2 h, and then used as precursors to synthesize homogeneous and size-controlled Cr2AlB2 powders at 900 degrees C for 2 h. The formation mechanisms involve in-situ reaction of Cr atom with B powders for CrB, and mutual migration of Al and CrB followed by Al intercalation for Cr2AlB2.