“…Using the thickness of the zirconia layer, the density of the oxide, 5.82 g/cm 3 [8], and the ZrO 2 molar mass M ZrO 2 , 123.22 g mol À1 , the amount of oxygen in the zirconia per unit surface area (=2 times number of oxidized Zr atoms) can be calculated and then the amount of oxygen dissolved from the zirconia into the bulk can be deduced by the variation of the thickness of the zirconia layer after each heat treatment.…”