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Precise Thermodynamics-Guided Boro/Carbothermal Synthesis of ZrB2 Powders
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DOI:10.1111/jace.70955.png)
Abstract
En 中文
A quantitative thermodynamic model based on the extreme assumption method and multicomponent multiphase equilibrium thermodynamics were established to control boron excess and carbon deficiency during vacuum boro/carbothermal reduction synthesis of ZrB2 powders, addressing volatilization of gaseous phases mainly includes BO (g), (BO)2 (g), and B2O3 (g). Using three systems (ZrO2-B4C, ZrO2-B, and ZrO2-B4C-C) at 1600°C as exemplars, all calculated proportions yielded single-phase ZrB2 powders with oxygen and carbon contents below 1 wt%. The ZrO2-B4C system gave the lowest oxygen and some rod-like particles; ZrO2-B route produced powders with very low carbon but higher oxygen content and coarser particles; ZrO2-B4C-C system achieved the finest particle size (D50 = 0.85 µm) with narrow distribution but slightly higher residual carbon. As-synthesized powders outperformed most commercial counterparts in oxygen content and particle size. Their impurities mainly originated from raw materials and varied with boron source, which were also briefly discussed.
Keywords:
boro/carbothermal reduction
impurities
powder synthesis
thermodynamic
ZrB2
Journal
IF:
3.8
Papers:
1.7W
Citations:
5.4W
