XPS studies on the leached surface layer of WAK-HLW glass

The surfaces of GP WAK1 glass specimens leached in distilled water at vario us pa-values were studied with X-ray photoelectron spectroscopy (XPS). Char acteristic changes in the composition of surface alteration products as wel l as in the ion-exchange zone in the glass were observed in dependence of t ime and pH and were compared to results of solution analyses. At low pH sur face alteration products consist of O, Si, Ti, Zr, Cr, Mo, Fe and P. At pH 7 to 9 a Mg-rich silicate with additions of Ca and Al is formed at the surf aces with a ratio of Si/Mg of about 2 independent of the S/Vratios used. Le aching of elements from the ion-exchange layer follows solubility/pH relati ons: In addition to Na and B, Ca, Ba, Ca and Mg are leached at low pH, whil e Mo is leached at high pH.