1. LaMaV Fundamentals of Crystal Nucleation and Growth in Glasses Edgar D. Zanotto www.certev.ufscar.br 1

2. LaMaV Center for Research Technology and Education in Vitreous Materials

3. LaMaV Vitreous materials lab 3 LaMaV

4. LaMaV Outline Introduction Importance of crystal nucleation, growth and overall crystallization Brief overview of glass transition Fundamentals Crystal nucleation in undercooled GF liquids Crystal growth Overall crystallization 4

5. LaMaV Properties of inorganic glasses Isotropic Transparent, opaque, colorless, colored. Refractive index: 1.2 – 2.2 Electrical conductivity (T amb ): 10  5 - 10  18 (ohm.cm)  1 T g : 150ºC - 1200 o C. Low thermal conductivity: k ≤ 1 W/m.K Hardness: 2 -15GPa Resistant to acids to soluble in H 2 O Fragile: K IC < 1 MPa.m 1/2 Conchoidal fracture... Metastable! Tend to devitrify on slow cooling or heating 5

6. LaMaV 6 “Devitrification is the chief factor which limits the composition range of practical glasses, it is an ever-present danger in all glass manufacture and working, and takes place promptly with any error in composition or technique” G. W. Morey The Properties of Glass Reinhold Pub, NY 1938 & 1954

7. LaMaV PTR glass Li 2 O.2B 2 O 3 Glass crystallization processes Nucleation: internal vs. surface, steady vs. non-steady, homogeneous vs. hetero, polymorphic vs. non-stoichiometric Growth: uni, two, tri-dimensional, single-crystals, spherulitic, dendritic, random, textured, diffusion controlled, polymorphic, single phase, multiphase … Overall Crystallization: combinations of the above listed cases 7

8. LaMaV Importance of crystal nucleation, growth and overall crystallization 8

9. LaMaV Importance and motivation If spontaneous crystallization is averted on the cooling path any liquid can vitrify; Viscous sintering can be arrested... Development of useful glass-ceramics with designed nano / micro / mm structures...and inusual properties 9

10. LaMaV 10 Mauro & Zanotto 200 years of glass... IJAGS, 2014 Most frequent keywords in the history of glass research

11. LaMaV R.Muller, V. Fokin, E.D. Zanotto- J. Non-Crystalline Solids (2001) Heterogeneous (surface) nucleation on silicate glasses Devitrite LS + CS 11

12. LaMaV Defect: devitrification 12

13. LaMaV Very few silicate glasses spontaneously display internal homogeneous nucleation (+ surface) Na 2 O  2CaO  3SiO 2 Li 2 O  2SiO 2 Homogeneous nucleation in stoichiometric silicate glasses 13

14. LaMaV Crystal nucleation and growth curves I max Homogeneous U max 14 Linear x Log scale?

15. LaMaV 15 Designed micro and nanostrucures lead to...

16. LaMaV 1nm 16

17. LaMaV Relaxation, T g 17

18. LaMaV Spec.volume TmTm T g 12 Temperature liquid supercooled liquid glass glass-ceramic Undercooling viscous liquids followed by isothermal crystallization Zero  18

19. LaMaV 1999, 2002, 2005, 2009, 20112010 19 2012 Books on nucleation and crystallization

20. LaMaV 20 2014 2011 2013 + Books on nucleation and crystallization

21. LaMaV References on GC + review articles by: Beall & Pinckney, Hoeland, Pannhorst, James, Davis, Zanotto, Dymshits… From glass to crystal: nucleation, growth and phase separation, from research to applications - D. Neuville et al. (2015) Nano-Glass Ceramics: Processing, Properties and Applications. Marghussian, V., 1 st Edition, Elsevier, 2015. 21

22. LaMaV Crystals in Glass: A Hidden Beauty E. D. Zanotto ISBN: 978-1-118-52143-4 136 pages, October 2013 22