ZrC (shell) and ZrO2 (core) (ZrC@ZrO2) core-shell nanopowders were in-situ synthesized by precipitating method using zirconium dioxide (ZrO2) and sucrose (C12H22O11). C12H22O11 was selected since it can be completely decomposed to carbon. Thus, carbon might be accounted precisely for the carbothermal reduction reaction. The ZrC@ZrO2 core-shell nanopowders were obtained with a molar ratio of C / Zr = 2 for the starting materials at 1500 oC for 2 hrs. The SEM photomicrograph reveals that ZrC@ZrO2 core-shell particles had an equiaxed morphology with a high surface rough. Furthermore, the size distribution of the particles was around 100 nm in diameter. Additionally, in the case of either C / Zr (mol.) > 1 or pyrolyzing temperature above 1400 oC, the thickness of ZrC shell could be increased. Moreover, the HR-TEM showed that the nanopowders possessed core-shell structure with ZrO2 core and ZrC shell, and the thickness of ZrC was about 10 nm carbothermally reduced at 1500 oC for 2 hrs with a molar ratio of C / Zr = 2

Keywords: ZrC@ZrO2, Core-shell, Nanopowders, In-situ, Thickness