TY - JOUR

T1 - Hydration and corrosion of polymerised aluminosilicate glasses

AU - Frischat, G. H.

AU - Leschik, M.

AU - Heide, G.

AU - Behrens, H.

AU - Wiedenbeck, M.

PY - 2010/4

Y1 - 2010/4

N2 - Natural and synthetic obsidian-type aluminosilicate glasses of different initial water contents were hydrated in D218O/(D,H) 218O fluids at 150 to 400°C and pressures up to 100 MPa. The diffusion/hydration profiles of 18O and D2O tr, analysed by SIMS and SNMS, displayed three regimes I, II, and III with readily discernable changes in slopes. Moreover, a corrosion process affecting the alkali and alkaline earth contents was observed; this process was found, at least in part, to be coupled to the diffusion/hydration processes. We have described these processes on the basis of the effective (apparent) diffusion coefficients for 18O and H2Ot *. Thus Deff-O(18) increases from ∼ 10 -19 m2/s to ∼ 10-15 m2/s between 150 and 400°C, whereas Deff-H2Ot*is similar to Deff at 200°C but is higher by approximately one order of magnitude at 400°C. An increase in the initial water content by a factor of 3 to 4 was found to accelerate the diffusion/hydration processes at 200°C by ∼ 1.5 orders of magnitude, whereas at 400°C no influence was seen. Such complex interdependencies can be modelled assuming that the corrosive process leads to the formation of OHgroups resultingin a depolymerisation of the glass network.

AB - Natural and synthetic obsidian-type aluminosilicate glasses of different initial water contents were hydrated in D218O/(D,H) 218O fluids at 150 to 400°C and pressures up to 100 MPa. The diffusion/hydration profiles of 18O and D2O tr, analysed by SIMS and SNMS, displayed three regimes I, II, and III with readily discernable changes in slopes. Moreover, a corrosion process affecting the alkali and alkaline earth contents was observed; this process was found, at least in part, to be coupled to the diffusion/hydration processes. We have described these processes on the basis of the effective (apparent) diffusion coefficients for 18O and H2Ot *. Thus Deff-O(18) increases from ∼ 10 -19 m2/s to ∼ 10-15 m2/s between 150 and 400°C, whereas Deff-H2Ot*is similar to Deff at 200°C but is higher by approximately one order of magnitude at 400°C. An increase in the initial water content by a factor of 3 to 4 was found to accelerate the diffusion/hydration processes at 200°C by ∼ 1.5 orders of magnitude, whereas at 400°C no influence was seen. Such complex interdependencies can be modelled assuming that the corrosive process leads to the formation of OHgroups resultingin a depolymerisation of the glass network.

UR - http://www.scopus.com/inward/record.url?scp=77952923032&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:77952923032

VL - 51

SP - 107

EP - 116

JO - Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B

JF - Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B

SN - 0031-9090

IS - 2

ER -