Nitridation of Zirconia

ZrO₂ can be nitrided partially by nitrogen at temperatures >1400°C. It is possible to describe all the synthesized phases with the general formula ZrO_2-2χN_4χ/3 (system ZrO₂-Zr₃N₄). Parameters–such as nitridation time, temperature, nitrogen pressure, and particle size–have a strong effect on the amount of incorporated nitrogen. Variation of these parameters allows the synthesis of Zr-O-N ceramics within a wide range of possible compositions. ZrO_2-2χcN4_χ/3 phases synthesized by reaction of ZrO₂ with nitrogen show ordered anion vacancies (β-type structures). β-type phases are non-transformable under mechanical stress at ambient temperature. Nitrogen-containing ZrO₂ shows very poor oxidation resistance. At temperatures >600°C, stability is found only in the presence of an oxygen getter.