High-entropy silicide ceramics developed from (TiZrNbMoW)Si2 formulation doped with aluminum

We report a success in synthesizing high entropy silicides (HES) compounds and manufacturing well-densified HES ceramics through spark plasma sintering. For a designed chemical formula as (Ti0.2Zr0.2Nb0.2Mo0.2W0.2)Si2, the as-synthesized HES showed a formula as (Ti0.22Zr0.06Nb0.29Mo0.22W0.21)Si2 with zirconium partially oxidized into zirconia. Doping with aluminum resulted in a HES with the same composition, promoted formation of ZrSi2 and Al2O3. XRD analysis of as-synthesized HES is well supported by the calculated diffraction data based on a 2 × 3x1 supercell with HCP crystal structure and experimental chemical composition. The cations in this HES crystal structure can occupy their positions randomly with little change of its lattice parameters and formation enthalpy.