Fine-grained dual-phase high-entropy ceramics derived from boro/carbothermal reduction

Pressureless sintering of dual‐phase, high‐entropy boride–carbide ceramics

“…The synthesis methods include co-synthesis, synthesis from commercial powders, sequential synthesis, and synthesis starting with TiC and commercial diboride powders, but HP or SPS at 2000 • C or higher is typically required for densification. [17][18][19][20] Relative densities for HP and SPS are typically higher than 90%, and grain sizes can be as low as approximately 0.6 µm. 17 The purpose of the present study was to sinter dualphase, high-entropy boride-carbide ceramics without applied pressure during sintering.…”

“…[17][18][19][20] Relative densities for HP and SPS are typically higher than 90%, and grain sizes can be as low as approximately 0.6 µm. 17 The purpose of the present study was to sinter dualphase, high-entropy boride-carbide ceramics without applied pressure during sintering.…”

“…Dual phase, HEB–HEC ceramics have been synthesized by a variety of techniques. The synthesis methods include co‐synthesis, synthesis from commercial powders, sequential synthesis, and synthesis starting with TiC and commercial diboride powders, but HP or SPS at 2000°C or higher is typically required for densification 17–20 . Relative densities for HP and SPS are typically higher than 90%, and grain sizes can be as low as approximately 0.6 µm 17 …”

High-aspect-ratio single-crystalline (HfxZr(1−x))B2 micron-rods: low-temperature, highly-efficient synthesis and oriented growth mechanism

“…It is well-known that the existence of a residual reducing agent (as the amorphous carbon under present conditions) is the prerequisite for ensuring the completion of reduction reactions. 30 Thus, it is reasonable to infer that in both the nucleation and growth process of (Hf 0.50 Zr 0.50 )B 2 , there always exist a certain amount of residual carbon, which plays an important role in enhancing the oriented growth of the {001} planes by elevating their specific surface free energies, so as to form (Hf 0.50 Zr 0.50 )B 2 single-crystals with a rod-like morphology.…”

Quantitative inspection of grain‐scale chemical inhomogeneities in high‐entropy AlB2‐type transition metal diborides

“…Previous studies of HE borides have assumed that compositional homogenization was reached after synthesis/sintering, that metal distribution was random across all scales (i.e., from short to large scale range), and that the metallic species were present in ideal equimolar proportions. [13][14][15][16][17][18][19][20][21][22][23][24] Some authors acknowledged deviations from equimolar metal ratios but have stood by the assumption of overall long-range chemical homogeneity. [20][21][22]25 Qin M. and coworkers studied a series of dual-phase HE UHTCs using Ti, Zr, Hf, Ta, and Nb as principal element.…”