Nitrogen incorporation into pure and doped zirconia

The defect chemistry of the nitrogen incorporation into pure and cation (Y3+, Eu3+, Ce4+, Mg2+, Ca2+)-doped ziconia is quantitatively described using simple thermodynamic considerations, allowing the calculation of the anion vacancy concentration as a function of the nitrogen and oxygen pressure in the surrounding atmosphere. The effective equilibrium constants for the nitrogen incorporation into pure and cation-doped zirconia (K  ) can be expressed by KPO2−3/2PN2=4[VOoo]N3/(1−3[VOoo]N)3 and KPO2−3/2PN2=(4[VOoo]N2([VOoo]N+[VOoo]Y))/(1−3[VOoo]N−[VOoo]Y)3, respectively, and are in the order of 10−25 at 1900 °C. Sievert's and Henry's law for gas solubility at high temperatures in melts and alloys were applied to model the results with only partial success.