Molten salt shielded synthesis (MS3) of Ti2AlN and V2AlC MAX phase powders in open air

Abstract

Synthesis of high-temperature carbide and nitride MAX phases requires an inert atmosphere to prevent oxidation. Energy and cost expensive conventional synthesis processes are not useful for large scale productions. Molten salt synthesis is simple but generally carried out in argon atmosphere. Molten salt shielded synthesis (MS3) is carried out in the air but needs salt encapsulation to prevent oxidation below melting point of the salt as reported earlier. In the present work, MS3 method without salt encapsulation in open air has been explored by using low melting eutectic salt mixture to provide oxidation shielding of the metal precursors at high temperature as well as to produce the required phase at lower temperature with shorter soaking time. In this paper, V2AlC and Ti2AlN have been synthesized using MS3 to obtain satisfactory phase purity. Therefore; this method can be extended to large scale industrial production through its eco-friendliness, sustainability and energy-efficient nature.