Zirconium diboride powders synthesized by boro/carbothermal reaction using sol-gel technology

Abstract

A single phase of zirconium diboride(ZrB₂)powder was successfully synthesized by sol-gel method in Zr-B-C-O system, using zirconium oxychloride(ZrOCl₂·8H₂O), nano-scale boron and sucrose(C₁₂H₂₂O₁₁)as the starting materials and propylene oxide(PO)as complexing agent at a low temperature. Simultaneously, the experimental and theoretical studies of ZrB₂ synthesized by boro/carbothermal reduction from novel sol-gel technology were discussed. The results indicated that the pure rod-like ZrB2 powder without residual ZrO₂ phase could be obtained with a B/Zr molar ratio of 3.5 at 1 400°C in argon atmosphere. Besides, in this study, a kinetic model for the Zr-B-C-O system producing ZrB₂ by boro/carbothermal reaction was established based on thermodynamic analysis. It was also observed that, with the increase of reaction temperature, the reaction which produced ZrB₂ powders changed from the borothermal reaction to boro/carbothermal reaction in the Zr-B-C-O system.

Keywords

zirconium diboride / boro/carbothermal reaction / kinetic model / sol-gel method

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