Synthesis of Nb₂AlC MAX Phase in KBr Protective Melt

The possibility of synthesis of Nb₂AlC MAX phase at varying temperature (900–1250°C) and molar ratio of initial reagents (powders of niobium, aluminum, carbon, as well as KBr salt, which performed a protective function in obtaining the target compound) has been studied. It has been found by X-ray powder diffraction that at low synthesis temperatures (900–1100°C) only intermediate products are obtained, and at the synthesis temperature of 900°C metallic niobium is also present. SEM and EDX-mapping data confirm the formation of the MAX phase at higher synthesis temperatures of 1200 and 1250°C. The effectiveness of decreasing the content of carbon in the initial mixture and increasing the aluminum content is shown. The thermal behavior in air current of the products obtained at temperatures of 900 and 1250°C has been studied.