Synthesis of nanolayered ternary borides powders (MAB phases) by sustainable molten salt shielded synthesis/sintering (MS3) process

In this paper, we report the synthesis of Fe2AlB2, Mn2AlB2, and MoAlB powders by using molten salt shielded synthesis/sintering (MS3)—a sustainable processing paradigm that uses no inert gas and relatively low temperatures to synthesize powders with uniform chemical composition and high phase purity. During this research, elemental powders were used as precursors powders in the presence of halide (NaCl, KBr, and NaCl–KBr) salts. Initially, the powders were cold-pressed; thereafter, they were encapsulated by salt. The encapsulated samples were then covered with salt and processed at a relative low temperature of 1000 °C. We observed that the synthesis of these powders was affected by the selection of the salts and stoichiometry of the starting powders. Predominantly single-phase powders of Fe2AlB2 and Mn2AlB2 powders were obtained in the KBr salt medium by using a nominal starting composition T2Al1.2B2 (T = Fe, Mn) without using shielding gas. Similarly, MoAlB powders were synthesized by using NaCl as a salt medium with MoAl1.2B2 nominal composition in air. This study shows that different types of ternary non-oxide ceramics can be synthesized in air in salt medium without using any shielding gas, thus increasing the ease and sustainability of production of non-oxide ceramics.