Synthesis and characterization of high‐entropy diboride microfibers

High‐entropy diboride (HEB) microfibers are in great demand for structural and functional applications in extreme conditions. Here, we synthesize (Hf, Ta, Nb, Mo, Ti)B 2 HEB microfibers through a two‐step technique involving thermal decomposition of polymers and subsequent boro/carbothermal reduction for the first time. Specifically, polymer precursor microfibers are first decomposed at a moderate temperature of 773 K, followed by a high‐temperature calcination at 2273 K to promote boro/carbothermal reduction. The resulting HEB microfibers, with a diameter of approximately 1 µm, exhibit a polycrystalline structure and high‐compositional uniformity from nanoscale to microscale. This work opens up a new way to synthesize innovative HEB microfibers.