Synthesis of nano-phase ZrC by carbothermal reduction using a ZrO2-carbon nano-composite

Carbothermal reduction of Zr-sucrose gels powders into nano-phase ZrC, or ZrC-Zr(C,O) core-shell powders, via a composite of 2-4 nm sized ZrO2 and amorphous carbon, is described. Samples with 1.7-20 sucrose-carbon:Zr ratio gels heated to 1495 degrees C at 10 degrees Cmin(-1), with 3 and 30 min hold time were studied in detail using; TG, XRD, SEM, TEM, STEM-EDX, and XPS with Ar+-ion etching. After 1495 degrees C, 3 min, the samples with 12-20C:Zr ratios yielded weakly agglomerated 30 to 40 nm sized ZrC particles, surrounded by a dense 5 nm thick shell of Zr(C,O). With 5C:Zr significant amounts of ZrO2 was present after heating at 1495 degrees C for 3 min, while after 30 min annealing, ZrC particles without residual amorphous carbon was obtained. Minor amounts of zirconia was found in most samples, which in similarity with the 5 nm Zr(C,O) shell, is believed to stem from post synthesis oxidation.

Automated summary

Carbothermal reduction of Zr-sucrose gels powders into nano-phase ZrC or ZrC-Zr(C, O) core-shell powders was achieved by using a composite of 2-4 nm sized ZrO2 and amorphous carbon. The resulting products varied in morphology and structure depending on the sucrose-carbon:Zr ratio in the gels.