Zirconia by Ionising Radiation

According to this study, the reason for discolouration could be alternately explained by excited electronic states and formation of activated colour centres. The replacement of Zr4+ by Y3+ in Y-TZP ceramic produced lattice vacancies in its oxygen sub-lattice according to 

In conclusion, colour changes of medical-grade Y-TZP induced by irradiation with ionising radiation such as y- or X-rays are related to two electron transitions at local lattice defects. The first defect is an intrinsic defect of type Y ZrO that is unstable, in particular at elevated temperatures, and can be correlated with 

TZP with electron sticking terms (0.7-1.3eV) and electron-hole (luminogenic) levels hv (TL) (1.72-2.3eV). (b) Temperature-and wavelength-resolved 3D-thermo- 

Alakoski, E., Tiainen, V.M., Soininen, A., and Konttinen, Y.T. (2008) Load-bearing biomedical applications of diamond-like carbon coatings — current status. Open Orthop.., 2, 43-50. 

(1993) Chemistry and properties of solids with the [NZP] skeleton. Solid State Ion., 63/65, 547 - 561. 

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