Influence of carbon on phase stability of tetragonal ZrO2

In the present work, nanocrystallite ZrO2 was synthesized by calcining zirconium (IV) acetylacetonate. X-ray diffraction results show the existence of tetragonal phase even when the nanocrystallite size reached ~47 nm. The presence of amorphous carbon was identified by Raman analysis while the Zr–C bonding was confirmed by X-ray photoelectron spectroscopy analysis. Transmission electron microscopy showed no hard-agglomeration in the samples treated at high temperatures. These results indicated that carbon has influence on the phase stability of t-ZrO2 in two aspects: the amorphous carbon creates a reducing atmosphere, meanwhile carbon atoms bonded with zirconium atoms act as a stabilizer.