Corrosion of Materials Course Corrosion of Inorganic Non-Metallic Materials part 3 Corrosion of glass Ales Helebrant, Antonin Jiricka Department of Glass and Ceramics ICT Prague, Czech Republic

Corrosion of Materials Course Contents Introduction, glass structure, main industrial glasses Partial processes of glass corrosion Development of kinetic models –Rana & Douglas –Hlaváč & Matěj –Boksay & Doremus –Strachan –DGC ICT model Examples Experimental testing of glass durability Thermodynamic approach (Plodinec, Conradt, Aagard & Helgeson) Conclusions and outlook

Corrosion of Materials Course Introduction – main industrial glasses Silica glass: –SiO 2 Water glass: –70 SiO 2 – 30 Na 2 O (wt.%) Flat glass, bottles: –72 SiO 2 – 12 CaO – 14 Na 2 O Crystal glass: –60 SiO 2 – 26 PbO – 14 K 2 O (PbO between 24-36) 3.3 glass (Pyrex, Simax): –80 SiO 2 – 15 B 2 O 3 – 5 Na 2 O Glass fibres: –53 SiO 2 – 15 Al 2 O 3 – 16 CaO – 4 MgO – 10 B 2 O 3

Corrosion of Materials Course Introduction – glass structure [Gedeon, Macháček]

Corrosion of Materials Course Introduction Hench, L.L.: in Physical Chemistry of Glass Surfaces, Proc. XI Intl. Cong. Glass (ed. Götz J.), ČVTS Prague 1977, Vol I. pp t>0t>0 glasssol. t=0 glass sol.

Corrosion of Materials Course Partial processes

Corrosion of Materials Course Kinetic models Rana & Douglas Rana M.A., Douglas R.W.: Phys. Chem. Glasses 2, 179 (1961) glasssol. glasssol. glasssol. glasssol.

Corrosion of Materials Course Kinetic models Hlaváč & Matěj Hlaváč J., Matěj J.: Ceramics-Silikáty 7, 261 (1963) glasssol. DADA a

Corrosion of Materials Course Kinetic models Boksay & Doremus Doremus, R.H.: Chemical durability of glass. In: Tomozawa, M;, Doremus, R.H. (eds.): Treatise on Materials Science and Technology 17, Academic Press 1979, pp glasssol. Hl-M. a DADA

Corrosion of Materials Course Kinetic models Strachan Strachan D.M.: in Wicks G.G., Ross W.A. (eds.) Advances in Ceramics, Vol. 8, Amer. Ceram. Soc., Columbus, Ohio 1984, p.12 Initial dissolution rate R 0 Congruent dissolution

Corrosion of Materials Course Kinetic models DGC ICT Helebrant A., Matoušek J.: Glastech. Ber. Glass Sci. Technol 68C1, 207 (1995) glasssol. Precip.layer

Corrosion of Materials Course Durability testing Glass Leaching PE solution grains vessel 3) 1)2) 1)Static (c s, k + ) 2)Dynamic (k +, k -, D/h) 3)VHT (precipitates)

Corrosion of Materials Course Examples Glass Composition (in mol%) –SK1 - 15% Na 2 O, 10%CaO, 75% SiO 2 –SK2 - 15% Na 2 O, 10%MgO, 75% SiO 2 Preparation –Pt/Rh crucible 1450°C – 1 hour –grinding – melting – 1 hour –cooling 500°C –fraction mm

Corrosion of Materials Course Examples Corrosion experiments –Polyethylene vessels –80°C –S/V= m -1 –up to 22 days Solution analysis – AAS (Atomic Absorption Spectroscopy) Surface analysis –SNMS (Secondary Neutral Mass Spectrometry) Glass Leaching PE solution grains vessel

Corrosion of Materials Course Examples Glass SK1

Corrosion of Materials Course Examples Glass SK2

Corrosion of Materials Course Examples Precipitation: CaO*3SiO 2 MgO*2.8SiO 2

Corrosion of Materials Course Thermodynamic approach Plodinec et al. Plodinec M.J. Jantzen C.M., Wicks G.G.: in Wicks G.G., Ross W.A. (eds.) Advances in Ceramics, Vol. 8, Amer. Ceram. Soc., Columbus, Ohio 1984, p.491 Metasilicates Oxides  G hydr ln Q Si

Corrosion of Materials Course Thermodynamic approach Conradt Conradt R.: J. Nucl. Mater. 298, 19 (2001) Phase diagram Silicates, oxides…  G + correction to glassy state H +, OH - on surface pH

Corrosion of Materials Course Thermodynamic approach Aagard & Helgeson Aagaard, P., Helgeson, H. C.: American Journal of Science, 282, 237 (1982) Semiempirical pH influence Arrhenius temperature dependence Saturation effect K=?

Corrosion of Materials Course TD approach - examples SK1 0.10

Corrosion of Materials Course TD approach - examples SK2

Corrosion of Materials Course TD approach - examples Time [days] congruent precipitation congruent SK1 SK2

Corrosion of Materials Course TD approach – examples SK1 supersaturation corrosion after 14 days undersaturation PHREEQC: Glass [mol/kg]

Corrosion of Materials Course TD approach – examples SK2 undersaturation corrosion after 14 days supersaturation PHREEQC: Glass [mol/kg]

Corrosion of Materials Course TD approach - examples Surface of SK1 after 2 days in deionised water, 80°C, S/V = 298,1 m -1, bar=100  m Surface of SK1 after 13 days in VHT, 200°C, S/V = 298,1 m -1, bar=10  m

Corrosion of Materials Course TD approach - examples Surface of SK2 after 2 days in deionised water, 80°C, S/V = 298,1 m -1, bar=50  m (left) 5  m (right)

Corrosion of Materials Course Conclusions & Outlook Aagard & Helgeson – influence of T, solution composition, back precipitation (geochemical code) Kinetic model – influence of S,V,F, interdiffusion Conradt – influence of solution pH, glass composition Back precipitation kinetics?

Corrosion of Materials Course Thank you