Hydrolysis Reactions at the Surface of Fluorozirconate Glass

The surface reaction products associated with the hydrolysis of ZBLA glasses have been characterized using X-ray photoelectron spectroscopy. The predominant surface reaction product in water and basic solutions is a zirconium (hydr)oxyfluoride species. The compositional analyses indicate that the (hydr)oxyfluoride which forms in water has an average oxygen-to-fluorine ratio of approx. 2/5. The Zr 3d binding energy of this (hydr)oxyfluoride species was interpreted on the basis of its Pauling charge; this verified the compositional analyses and suggested a seven-coordinate surface species of the form ZrO//2F//5 or Zr(OH)//2F//5. It is proposed that zirconium (hydr)oxyfluoride is created in all aqueous solutions because of attack of Zr-F bonds by molecular water.