In situ synthesis of ZrB₂–ZrC–SiC ultra-high-temperature nanocomposites by a sol–gel process

ABSTRACT

ZrB₂–ZrC–SiC is one of the ultra-high-temperature ceramic composites with excellent properties. In this research, high-purity ZrB₂–ZrC–SiC nanopowders were synthesised using a carbothermal reduction reaction at a relatively low temperature (1370°C) from cost-effective zirconium(IV) chloride by a sol–gel method. The effect of heat treatment temperature on the synthesis of ZrB₂–ZrC–SiC composite powder was studied. X-ray diffractometry results showed that the phases ZrB₂, β-SiC and ZrC were synthesised at 1370°C. The mean crystallite sizes for each of the phases were calculated using the Scherrer method. The specific surface area for the sample calcined at 1370°C was 81.479 m² g⁻¹. SEM observation revealed that the particles had a size lower than 250 nm. Backscattered electron image and map analysis with scanning electron microscopy showed that a suitable phase homogeneity was achieved, as confirmed by energy-dispersive X-ray spectroscopy.

KEYWORDS:

• Sol–gel synthesis
• ZrB₂–ZrC–SiC
• composite
• phase analysis
• surface area
• morphology

Disclosure statement

No potential conflict of interest was reported by the authors.