IRRADIATION-INDUCED COLOR CHANGES IN MEDICAL GRADE Y-TZP CERAMICS

Various solid state spectroscopy techniques applied to zirconia (Y-TZP ) ceramic femoral ball heads for total hip replacement showed that the ir pronounced colour change, after gamma sterilisation, from off white to a purplish grey shade, can be related to two electronic transition s at local defects in the crystal lattice. From the experimental resul ts it can be safely concluded that the colour changes are not caused b y elevated impurity levels and thus do not compromise the required mec hanical or chemical performance of the material.