Corrosion of Materials Course Corrosion of Inorganic Non-Metallic Materials Aleš Helebrant Department of Glass and Ceramics ICT Prague, Czech Republic

Corrosion of Materials Course Contents Inorganic Non-Metallic Materials Principles of INM corrosion, congruent and incongruent dissolution Control mechanisms of dissolution, mathematical description Corrosion of ceramics Corrosion of glass Enamels as surface layers on metals Corrosion of concrete –Typical examples of materials –Corrosion mechanisms –Increasing chemical durability

Corrosion of Materials Course Literature for further study McCauley R.A.: Corrosion of Ceramics. Marcel Dekker, Inc. New York 1995 Clark D.E., Zoitos B.K. (eds.): Corrosion of Glass, Ceramics and Ceramic Superconductors. Noyes Publications, Park Ridge, New Jersey, 1992 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 Helebrant A.: Kinetics of corrosion of silicate glasses in aqueous solutions. Ceramics-Silikáty 41, (1997) Helebrant A., Jiřička A., Jiřičková J.: Corrosion of glass. Glass Sci. Tech. 77C, (2004) Jiřička A. et al.: Corrosion modeling of simple glasses from the systems SiO 2 - Na 2 O-CaO and SiO 2 -Na 2 O-MgO. Glass Sci.Tech. 76, (2003) Jiřička A., Helebrant A.: Dissolution of soda-lime, silica and high-level waste glass by single-pass flow-through and static tests. In: Environmental Issues and Waste Management Technologies in the Ceramic and Nuclear Industries V (Ceramic Transactions, Vol 107, eds. Chandler G.T., Feng X.), The American Ceramic Society, Westerville, OH, USA, 2000, pp

Corrosion of Materials Course Inorganic Non-metallic Materials INM –Ceramics –Glass –Inorganic binders (cement, gypsum) –Monocrystals –Glass-ceramics –Inorganic Non-Metallic Materials = Ceramics (US) –Ceramics (UK) = pottery, construction ceramics, porcelain, refractories..... Traditional INM – based on silicates or silica

Corrosion of Materials Course Structure of INM cristobalite

Corrosion of Materials Course Structure of INM K 2 O-SiO 2 glass

Corrosion of Materials Course Structure of INM silica glass crystalline silica (quartz)

Corrosion of Materials Course Structure of INM periclase MgO

Corrosion of Materials Course Structure of INM zeolite

Corrosion of Materials Course Corrosion of INM corrosion of metals – electrochemical process corrosion of INM – dissolution –reaction with liquids (aqueous solutions, melts) –reaction with gasses sometimes connected with subsequent degradation

Corrosion of Materials Course Dissolution congruent incongruent t=0 t>0t>0

Corrosion of Materials Course Congruent dissolution solidusliquidus 1) surface reaction 2) transport of surface reaction products into the solution bulk (diffusion) Which process controls the overal rate of dissolution?

Corrosion of Materials Course Models of congruent dissolution non-steady diffusion steady state diffusion surface reaction surface reaction and steady state diffusion

Corrosion of Materials Course Diffusion – Fick‘s laws

Corrosion of Materials Course Non-steady diffusion saturated conc c s conc. in bulk solution c l

Corrosion of Materials Course Error function

Corrosion of Materials Course Non-steady diffusion

Corrosion of Materials Course Steady-state diffusion saturated conc. c s conc. in bulk solution c l h

Corrosion of Materials Course Steady-state diffusion

Corrosion of Materials Course Surface reaction conc. in bulk solution c l saturated conc. c s

Corrosion of Materials Course Surface reaction

Corrosion of Materials Course SR comparable with SD saturated conc. c s conc. in bulk solution c l h c‘<c s

Corrosion of Materials Course SR comparable with SD

Corrosion of Materials Course Saturation effect