Nano-TiC obtained through a reaction of MWCNTs with Zr(Y,Ti)O2.
The zirconia nanopowder stabilized with 2.5 mol% Y(2)O(3) and doped with 18 mol% TiO(2) (Zr(Y,Ti)O(2)) was homogenized with 5.2 wt% multiwall carbon nanotubes (MWCNT) through colloidal processing. The resultant mixture was heat-treated for 2 h at 1200 degrees C in vacuum under a pressure of 5 x 10(-4) mbar. The microstructure characterization was performed using the TECNAI FEG (200 kV) SuperTWIN transmission electron microscope, equipped with the integrated EDAX detector. The TEM observations of the as-received samples showed single strands of the carbon nanotubes uniformly dispersed among zirconia crystallites. Heat treatment of the Zr(Y,Ti)O(2)-MWCNT mixture caused the transformation of carbon nanotubes into polycrystalline TiC nanofibres and nanorods as confirmed by both the energy dispersive X-ray spectroscopy microanalysis and the high-resolution electron microscopy (HREM) observations. Relying on the above, a mechanism of the TiC in situ crystallization controlled by carbon diffusion through the newly formed TiC phase was discussed.
Pyda
W
W
AGH University of Science and Technology, Cracow, Poland.
Morgiel
J
J