Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides

The fabrication by Spark Plasma Sintering (SPS) of bulk high entropy ceramics from powders obtained Self-propagating High temperature Synthesis (SHS) is addressed in this work. effect produced the introduction 1 wt.% graphite to before SPS investigated under different conditions. final density and composition sintered (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 (Hf0.2Mo0.2Zr0.2Ti0.2Nb0.2)B2 are found be negatively affected presence oxide impurities powders. While product can progressively improved when increased 1800 1950 °C, residual porosities remain relatively if using additive-free In contrast, wt.%C markedly allows for oxides elimination carbothermal reduction mechanism. Products consolidation correspondingly enhanced so that relative densities about 97% attained. Other than latter effect, surface removal also makes more reactive, thus synthesis single-phase products promoted. particular, fully homogeneous at lower conditions (1850 °C).