Abstract:Theoretical calculations have unequivocally demonstrated that within the MAX phase, Nb2PC showcases superior mechanical properties in comparison to its counterparts, rendering it a profoundly promising material for structural applications. Regrettably, extensive exploration into phosphorus-containing MAX phases has been overlooked due to formidable challenges, including exorbitant raw material expenses (necessitating high-purity metals, red phosphorus, and graphite powders), intricate reactor designs (mandating reactions within sealed quartz reactors), and protracted reaction durations (owing to phosphorus's low boiling point, necessitating a prolonged low-temperature phosphating/high-temperature reaction process for MAX phase synthesis). Drawing from these challenges, this paper introduces an innovative strategy for the high-temperature phosphating synthesis of phosphorus-containing MAX phases, rooted in gas-solid reaction mechanisms. Leveraging the elevated release of phosphorus vapor from FeP in the by-product ferrophosphorus slag during yellow phosphorus production, this method facilitates the phosphating of NbC—a carbon thermal reduction product of Nb2O5—at elevated temperatures, culminating in the successful and efficient production of the Nb2PC MAX phase. Furthermore, the study delves into the influence of raw material ratios, sintering temperature, and duration of thermal retention on product purity. The results indicate that when the molar ratio of NbC to ferrophosphorus slag is 1:5, a purity of greater than 99% of Nb2PC can be obtained by holding at 1200 ℃ for 1 hour. This pioneering approach holds great promise in establishing a technical foundation for the cost-effective and large-scale fabrication of phosphorus-containing MAX phases.