Physical characterization of glassy materials using ultrasonic non destructive

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Physical characterization of glassy materials using ultrasonic non destructive

  1. 1. Physical Characterization of Glassy Materials Using Ultrasonic Non-Destructive Technique Sidek Ab Aziz Department of Physics, Faculty of Science Universiti Putra Malaysia 43400 UPM Serdang, Selangor Seminar on Materials Science and Technology 2013, June 24, 2013, ITMA
  2. 2. General Discussion Glass (amorphous) Crystalline
  3. 3. Scope of Presentation Free Web 2.0 Apps. http://mindmap.crazenut.org
  4. 4. What is a glass? Glass - hard, brittle solid material that is normally lustrous and transparent in appearance and shows great durability under exposure to the natural elements. Obsidian - super- heated sand or rock that rapidly cooled. Moldavite formed by meteorite impact (Besednice, Bohemia) 4 obsidianites, kind of alumino-silicate (SiO2–Al2O3) glasses containing crystalline particles such as Fe2O3.). Man- Made Glass
  5. 5. Principles of Glass Formation 5 Glass (amorphous) Crystalline The viscosity increases with undercooling until the liquid freezes to a glass Crystals  ordered atomic structures mean smaller volumes (high density) & lower energies  thermodynamically stable phase Glasses  lack of long-range order results in larger volumes (lower density), higher energies;  thermodynamically metastable phase Knowledge of glass structure is important which relates to other Free Web 2.0 Apps. http://www.text2mindmap.com
  6. 6. Silicate Borate • Glass structure has short range order but no long range order. • Silicate tetrahedra link up to form 3D glass network. • Some ions such as Na will modify the network but are not part of it. Some structural groupings in borate glasses as indicated from nuclear magnetic resonance experiments (Bray 1985). Small solid circles represent boron atoms, open circles oxygen atoms and an open circle with negative sign indicates non-bridging oxygen. Glass Structure
  7. 7. Bonding Structure of Tellurite 2D chain: crystalline TeO2 TeO2 chains Deformation and breaking of TeO2 chain by modifier The structure basic TeO2 –based glass structural unit namely, TeO4 trigonal bipyramids (tbp) and TeO3 trigonal pyramid (tp) . TeO4 tbp TeO3 tp Both structure have a lone pair of electron in one of its equatorial /axial sites. 7 Phosphate Basic glass former, P2O5 Effects of Mg cation content on the phosphate glass
  8. 8. Glass Sample Preparation www.glassforever.co.uk/howisglassmade/ glass furnace cooling systems 8
  9. 9. 9 Some pigments used to produce coloured glass Compounds Colors Compounds Colors iron oxides greens, browns selenium compounds reds manganese oxides deep amber, amethyst, decolorizer carbon oxides amber/brown cobalt oxide deep blue mix of mangnese, cobalt, iron black gold chloride ruby red antimony oxides white uranium oxides yellow green (glows!) sulfur compounds amber/brown copper compounds light blue, red tin compounds white lead with antimony yellow
  10. 10. Research Project To produce the fiber optics and flat glasses for the future applications Glass Research @ UPM  Fiber Optics are cables that are made of optical fibers that can transmit large amounts of information at the speed of light. (www.dictionary.com)  Dominated by Silicate based glass
  11. 11. Glass Research @ UPM Key Researchers A goal of solid-state science, which intends to give universal understandings of macroscopic properties through simple theories on the basis of known atomic structures. 11
  12. 12. Glass Research @ UPM 12 Tellurite (TeO2) Phosphate (P2O5) Borate (B2O3) Lithium Chloroborate Lead Borate Lead Bismuth Borate Bismuth Borate Zink Chloride Phosphate Silver Phosphate Lithium Phosphate Lithium Chlorophosphate Lead Magnesium Chlorophosphate Lead Bismuth Phosphate Lithium Chloride Phosphate Lithium Zink Phosphate Lead Zink Metaphosphate Zinc magnesium phosphate Zinc Tellurite Borotellurite Zinc oxyfluorotellurite Lead Borotellurite Silver Borotellurite Zinc Neodymium Tellurite Zinc borotellurite Zinc oxyfluorotellurite Ferum Tellurite Glass research activities conducted at the Universiti Putra Malaysia. Formation Physical Studies Elastic Properties Optical Characterization Thermal Properties Dielectric Properties Research Scope
  13. 13. Glass Research @ UPM 13 Tellurite (TeO2)Phosphate (P2O5) Borate (B2O3) Selected some of the prepared binary and ternary glass samples at the Department of Physics, Universiti Putra Malaysia. Ag2O-B2O3 PbO-B2O3 Bi2O3-B2O3 Li2O-P2O5 PbO-B2O3 PbCl2-P2O5 LiCl-P2O5 ZnCl2-P2O5 B2O3-TeO2 ZnO-TeO2 Fe2O3-TeO2 PbO-Bi2O3-B2O3 LiCl-Li2O-P2O5 PbCl2-MgO- P2O5 Li2O-ZnO-P2O5 PbO-ZnO-P2O5 PbO-Bi2O3-P2O5 Cu2O-CaO-P2O5 Ag2O-B2O3-TeO2 PbO- B2O3-TeO2 ZnO- B2O3-TeO2 Nb2O5- ZnO- TeO2 AlF-ZnO-TeO2 binary ternary
  14. 14. Glass Oxide Former Modifier Glass Samples Researchers Binary Oxide Glass Series Borate (B) Silver (Ag) Ag2O-B2O3 Sidek et al. (1994) Lead (Pb) PbO-B2O3 Azman et al. (2002) Bismuth (Bi) Bi2O3-B2O3 Sidek et al.(2007) Phosphate (P) Lithium (Li) Li2O-P2O5 Low et al. (1999) Sidek et al.(2003) Lead (Pb) PbO-B2O3 Azman et al. (2002) Talib et al. (2003) Lead Chloride (PbCl2) PbCl2-P2O5 Talib et al. (2003) Lithium Chloride (LiCl) LiCl-P2O5 Loh et al. (2005) Tellurite (Te) Boron (B) B2O3-TeO2 Halimah et al.(2005) Sidek et al.(2006) Zink (Zn) ZnO-TeO2 Rosmawati et al. (2008) Sidek et al.(2009) Ferrum (Fe) Fe2O3-TeO2 Zarifah et al. (2010) PbO-P2O5 B2O3-TeO2 Ag2O-B2O3 Glass samples prepared by melt quenching technique @ UPM
  15. 15. Glass Former Network Modifier Glass Samples Researchers Ternary Oxide Glass Series Borate (B) Bismuth (Bi) Lead (Pb) PbO-Bi2O3-B2O3 Sidek et al. (2005) Hamezan et al.(2006) Phosphate (P) Lithium (Li) Lithium Chloride (LiCl) LiCl-Li2O-P2O5 Low et al. (1999) Sidek et al.(2003) Magnesium (Mg) Lead Chloride (PbCl2) PbCl2-MgO-P2O5 Sidek et al.(2004) Zink (Zn) Lithium (Pb) Li2O-ZnO-P2O5 Sidek et al.(2005) Zink (Zn) Lead (Pb) PbO-ZnO-P2O5 Sidek et al.(2005) Bismuth (Bi) Lead (Pb) PbO-Bi2O3-P2O5 Sidek et al.(2006) Calsium (Ca) Copper (Cu) Cu2O-CaO-P2O5 Talib et al. (2008) Tellurite (Te) Boron (B) Silver (Ag) Ag2O-B2O3-TeO2 Halimah et al. (2005) Zink (Zn) Aluminum Floride (AlF) AlF-ZnO-TeO2 Sidek et al.(2009) Boron (B) Lead (Pb) PbO- B2O3-TeO2 Iskandar et al. (2010) Zink (Zn) Neodymium (Nb) Nb2O5- ZnO- TeO2 Mohamed et al. (2010) Boron (B) Zink (Zn) ZnO- B2O3-TeO2 Ayuni et al (2011) Selected some of the prepared ternary glass samples at the Department of Physics, Universiti Putra Malaysia. GeO2-PbO-Bi2O3 AgI-B2O3-TeO2 PbO-B2O3
  16. 16. SEM Photos XRD Pattern of Starting Materials TeO2 powder TeO2 glass ZnO Powder TeO2-ZnO glass 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 10 20 30 40 50 2 theta Intensity(a.u) 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 10 20 30 40 50 2 Theta Intensity(a.u) 0 5000 10000 15000 20000 25000 30000 35000 10 20 30 40 50 2 Theta Intensity(a.u) TeO2-ZnO-AlF3 glass AlF3 (97.0%) Powder 16
  17. 17. XRD patterns 100 600 1100 1600 2100 10 20 30 40 50 2 theta Intensity(a.u) TZ7 TZ6 TZ5 TZ4 TZ3 TZ2 TZ1 TZ0 • no discrete or continuous sharp peaks • but broad halo at around 2 260 - 300, which reflects the characteristic of amorphous materials. • absence of long range atomic arrangement and the periodicity of the 3D network in the quenched material 400 600 800 1000 1200 1400 1600 1800 10 20 30 40 50 2 theta Intensity(a.u) S5 S4 S3 S2 S1 TeO2)1-x (ZnO)x (x = 0.1 to 0.4 in 0.05) (TeO2)90(AlF3)10-x(ZnO)x (x = 1 to 9) binary ternary 17
  18. 18. Ultrasonic System Schematic representation of (a) simple pulse ultrasonic system. (b) Envelope of pulse echo train and (c) detail of each echo as seen on oscilloscope display 18
  19. 19. Ultrasonic Pulse Echo Overlap System Pulse echo overlap system Pulse echo overlap waveforms Block diagram of the experimental set up – ultrasonic wave velocity and attenuation measurement (Mepco Engineering College, INDIA) 19
  20. 20. Ultrasonic System Ultrasonic – MBS 8000 Ultrasonic Data Acq. System 20
  21. 21. 21 Important Physical Properties Density is defined as the mass per unit volume. – Density is an intensive property of matter, meaning it remains the same regardless of sample size. – It is considered a characteristic property of a substance and can be used for material’s classification Density Measurement (Archimedes Method) ac aca a s ww w          Molar volumes  M V 
  22. 22. Physical Properties Variation of density and molar volume with mol% Bi2 O3 in Bi2 O3–B2 O3 glass systems. The increase of the density of the glasses accompanying the addition of Bi2 O3 is probably attributable to a change in cross-link density and coordination numbers of Bi3+ ions. 26 26.5 27 27.5 28 28.5 29 0.55 0.6 0.65 0.7 0.75 0.8 0.85 Mole fraction of TeO2 Molarvolume(cm3 mol-1 ) 4650 4700 4750 4800 4850 4900 4950 5000 Density(kgm-3 ) Density and molar volume of TeO2.B2O3 glasses 28 28.5 29 29.5 30 30.5 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Pecahan Mol Ag2O Isipadumolar(cm3 ) 4800 4900 5000 5100 5200 5300 Ketumpatan(kg/m3 ) Density and molar volume of [(TeO2)x (B2O3)1-x)]1-y [Ag2O]y 22
  23. 23. Density and Molar Volume 3500 4500 5500 6500 7500 0 20 40 60 80 Bismuth Oxide (mol%) Density(kgm-3) Dependence of density on the composition of bismuth oxide glass systems as measured by El-Adawy and Moustafa (1999) (5 - 45 mol%), Wright et al (1977) (20 – 42.5 mol%) and present works (40 – 70 mol%). 23
  24. 24. Density & Molar Volume 4700 4800 4900 5000 5100 5200 5300 5400 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 Mole fraction of ZnO Density(kg/m 3 ) 22 24 26 28 30 32 34 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 Mole fraction of ZnO Molarvolume(10 -6 m 3 mol -1 ) •Similar behaviour as El- Mallawany (1993). •Addition of ZnO causes some type of structural rearrangement of the atoms (Hoppe et al. (2004). •Possibility for the alteration of the geometrical configuration upon substitution of ZnO into the tellurite glassy network. 24
  25. 25. Density & Molar Volume 4700 4800 4900 5000 5100 5200 5300 5400 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 Mole fraction of ZnO Density(kg/m 3 ) 22 24 26 28 30 32 34 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 Mole fraction of ZnO Molarvolume(10 -6 m 3 mol -1 ) •The increase in density indicates zinc ions enter the glassy network •The decreases in the molar volume was due to the decrease in the bond length or inter-atomic spacing between the atoms • The stretching force constant (216 N/m – 217.5 N/m) of the bonds increase resulting in a more compact and dense glass. • Atomic Radius (Shelby, 2005). •R(Zn2+)(0.074 nm) << R(Te2+)(0.097 nm) •there is no anomalous structural change (non-linear behaviour) 25
  26. 26. Elastic constants of the glasses Longitudinal modulus Shear modulus Bulk modulus Poisson’s ratio Young’s modulus Debye Temperature 2 lVL  2 sVG         22 3 4 sl VVK     22 22 2 2 sl sl VV VV      22 222 43 sl sls VV VVV E     mDt V M Np k h 3 1 4 9           3 1 33 12           lS m VV V 26
  27. 27. 27 [(TeO2)65(B2O3)35]1–y[Ag2O]y glasses (Halimah et al. 2010) Pure and WO3 dopedCeO2–PbO–B2O3 glasses (Singh & Singh 2011) Figure 17 Density and molar volume of selected glass samples. Table 6 Measured density (ρ), molar volume (V), longitudinal ultrasonic velocity (vl), shear ultrasonic velocity (vs), elastic moduli, Poisson's ratio (σ), and fractal dimension (d = 4G/K ) and (E/G) ratio of (TeO2)90(AlF3)10-x(ZnO)x glasses (Sidek et al. 2009). Elastic modulus of zinc oxyfluorotellurite glasses
  28. 28. Ultrasonic Wave Velocity Compositional dependence of the velocity of longitudinal and shear acoustic waves in Bi2 O3–B2 O3 glass systems. Both increase at first with increasing Bi2 O3 mol% up to a maximum at 25 mol% Bi2 O3 and then decrease as the Bi2 O3 mol% increases further. 1000 1500 2000 2500 3000 3500 4000 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Pecahan mol of Ag2O Halajuultrasonik(m/s) Compositional dependence of the velocity of longitudinal and shear acoustic waves in [(TeO2)x (B2O3)1-x)]1-y [Ag2O]y glass 1500 2000 2500 3000 3500 4000 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 Mole fraction of ZnO Velocity(m/s) Longitudinal Longitudinal Shear Shear Compositional dependence of the velocity of longitudinal and shear acoustic waves in [(ZnO)(TeO2) glass 28
  29. 29. Ultrasonic Wave Velocity Lead Magnesium Chloride Phosphate Glass 29
  30. 30. Elastic Modulus Dependence of longitudinal modulus on the composition of Bi2 O3–B2 O3 glass systems. One reason for this difference may come from the volume effect, in that C44 expresses the resistance of the body to deformation where no change in volume is involved, while C11 expresses the resistance where compressions and expansions are involved. 10 20 30 40 50 60 70 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Pecahan mol Ag2O Moduluskenyal(GPa) L E K G Compositional dependence of the longitudinal and shear modulus of [(TeO2)x (B2O3)1-x)]1-y [Ag2O]y glass 30
  31. 31. Elastic Moduli 15 20 25 30 35 40 45 50 55 60 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 Mole fractionofZnO ElasticModuli(GPa) Longitudinal Modulus, L Young’s Modulus, E Bulk Modulus, K Shear Modulus, G 31
  32. 32. Elastic Properties Mole fraction, x 0.3 0.4 0.45 0.5 0.6 Elastic stiffness (GPa) C11 C44 C12 48.9 18.0 12.9 48.8 18.0 12.7 47.5 17.4 12.7 47.3 17.5 12.3 47.3 17.2 13.0 Young's modulus, E (GPa) 43.5 43.5 42.2 42.2 41.8 Bulk modulus, B (GPa) 24.9 24.7 24.3 24.0 24.4 Poisson's ratio,  0.208 0.207 0.211 0.207 0.215 Fractal dimension 2.90 2.92 2.87 2.92 2.82 Molar volume, V (cm3/mole) 34.2 33.8 34.2 33.9 33.3 Number of atoms per volume (x1028 atoms/m3) 9.67 8.90 8.37 8.00 7.24 Debye Temperature (K) 291 275 263 255 238 The room temperature elastic properties of (PbO)x(P2O5)1-x glasses Mole fraction, y 0.04 0.06 0.07 0.1 Elastic stiffness (GPa) longitudinal, c11 shear, c44 c12 50.4 17.1 16.3 44.3 16.0 12.3 43.0 15.9 11.2 35.7 14.8 6.03 Young's modulus, E (GPa) 42.4 39.0 38.4 33.9 Bulk modulus, B (GPa) 27.6 23.0 21.8 15.9 Poisson's ratio,  0.244 0.217 0.206 0.145 Fractal dimension 2.47 2.79 2.92 3.73 Molar volume, V (cm3/mole) 33.5 33.5 33.3 33.4 Number of atoms per volume (x1028 atoms/m3) 9.60 9.65 9.72 9.78 Debye Temperature (K) 276 266 264 251 Room temperature elastic properties of (PbCl2)y(PbO.2P2O5)1-y glasses 32
  33. 33. Elastic Properties 33
  34. 34. 34 Elastic properties of ZnO-TeO2 glasses (Sidek et al. 2010) 1500 2000 2500 3000 3500 4000 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 Mole fraction of ZnO Velocity(m/s) 15 20 25 30 35 40 45 50 55 60 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 Mole fraction of ZnO ElasticModuli(GPa) 0.19 0.2 0.21 0.22 0.23 0.24 0.25 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 Mole fraction of ZnO Poisson'sRatio 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 Mole fraction of ZnO Microhardness(GPa) Shear Longitudinal L E K G Ultrasonic velocities Elastic moduli Poisson’s ratio Micro-hardness
  35. 35. 35 Elastic moduli of selected binary glassy materials. Elastic Moduli (GPa)  Material Density L G K E References 15Sm2O3-85P2O5 3.280 66.42 23.63 34.91 57.84 0.224 Sidek et al. (1988) 15La2O3-85P2O5 3.413 67.63 23.05 36.90 57.23 0.241 Sidek et al. (1988) 15Nd2O3-85P2O5 3.233 70.50 24.80 37.40 60.90 0.229 Senin et al. (1993) 15Bi2O3-85P2O5 4.418 56.8 19.2 31.2 47.9 0.244 Sidek et al. (2011) 20Ho2O3-80P2O5 3.327 73.1 24.7 40.1 Senin et al. (1996) 20Nd2O3-80P2O5 3.358 67.4 24.1 35.3 58.8 0.22 Sidek et al. (1993) 20Sm2O3-80P2O5 3.326 63.1 23.4 31.9 56.5 0.20 Sidek et al. (1993) 20Ce2O3-80P2O5 3.254 74.4 25.0 41.1 62.3 0.23 Sidek et al. (1993) 14Ag2O-86B2O3 2.850 44.15 13.37 26.32 Saunders et al. (1987) 20PbO-80B2O3 3.801 45.4 14.70 25.90 43.0 0.262 Azman et al. (2002) 40PbO-B2O3 4.852 76.09 25.15 42.54 63.04 0.253 Sidek et al. (2003) 40Bi2O3-B2O3 5.262 74.67 27.70 37.75 66.75 0.205 Sidek et al. (2003) 30PbO-70B2O3 4.019 71.40 22.80 41.00 57.60 0.265 Azman et al. (2002) 30PbO-70P2O5 4.135 47.30 15.70 24.00 39.20 0.252 Azman et al. (2002) 26Tb2O3-74P2O5 3.578 76.2 25.4 42.00 64.0 0.246 Senin et al. (1994) 26Ce2O3-74P2O5 3.234 72.5 24.00 40.60 60.00 0.233 Saunders et al. (2001) 26Pr2O3-74P2O5 3.338 74.3 24.3 41.9 61.1 0.257 Senin et al. (2000) 33Ag2O-67B2O3 4.030 72.18 19.17 46.61 Saunders et al. (1987) 30ZnO-70TeO2 5.211 56.06 19.39 30.21 47.92 0.236 Rosmawati et al. (2008)
  36. 36. 36 Elastic moduli of selected binary glassy materials (cont) 33ZnCl2-67TeO2 4.63 50.8 15.10 30.6 39.0 0.289 El-Mallawany et al. (1998) 30V2O5-70TeO2 4.564 44.1 11.5 28.8 30.5 0.289 El-Mallawany et al. (1998) 30B2O3-70TeO2 4.89 63.62 23.33 32.51 56.48 0.21 Halimah et al. (2007) 30B2O3-70TeO2 4.78 0.21 Sidek et al.(2006) TeO2 (pure glass) 5.101 56.40 19.90 Sidek et al. (1989) TeO2 (pure glass) 5.105 59.1 20.6 31.7 50.7 0.233 El-Mallawany et al. (1998) TeO2 (pure crystal) 6.02 56.0 27.2 Arlt & Schweppe (1968) P2O5 (pure glass) 2.52 12.1 Bridge et al. (1984) SiO2 (pure glass) 2.203 30.7 Borgadus et al. (1965) So far silicate based glasses are practically well employed by engineers for optoelectronic devices development and application. However silicate glass has some disadvantages. As an alternative, more researchers are now preferred tellurite based glass to be used as a host matrix in laser applications. We also found that tellurite is the best glass host due to low melting temperature and in absence of hygroscopic properties as compared to borate and phosphate based glasses.
  37. 37. Potential Application of Glassy Materials CD memory device Optical switching device Non-linear optical devices Electrochemical devices Laser host Infra-Red Fiber Optics 37
  38. 38. 38
  39. 39. Next-generation large-scale panels Glass substrates for LCDs Next-generation large-scale panels by contributing to form various functional films on glass substrates. 39
  40. 40. …you could see what was in the fridge without opening it? …you could have a fish tank which is self cleaning? Self cleaning glass 40 When water hits a hydrophilic surface, it flattens and spreads out to form a thin sheet. Hydrophilic surface =wetting Water spreads HYDROPHOBIC (WATER HATING) When water hits a hydrophobic surface, it beads. Hydrophobic surface = beading Water beads HYDROPHILIC (WATER LOVING) Poor wetting (beading) Contact angle > 90° Good wetting Contact angle < 90°
  41. 41. When water hits a hydrophilic surface, it flattens and spreads out to form a thin sheet. Hydrophilic surface =wetting Water spreads HYDROPHOBIC (WATER HATING) When water hits a hydrophobic surface, it beads. Hydrophobic surface = beading Water beads HYDROPHILIC (WATER LOVING) Poor wetting (beading) Contact angle > 90° Good wetting Contact angle < 90° 41
  42. 42. SELF CLEANING GLASS THE LOTUS LEAF EFFECT The leaves of Lotus plants have the unique ability to avoid getting dirty. They are coated with wax crystals around 1 nanometre in diameter and have a special rough surface. Droplets falling onto the leaves form beads and roll off taking dirt with them, meaning the leaves are self-cleaning. Sometimes referred to as “The Lotus Leaf effect” Scientists have mimicked nature at the nanoscale to create glass surfaces that are ‘self-cleaning’ like the Lotus leaf. No more scrubbing of shower screens! Self cleaning glass Normal glass No more Spiderman window cleaner! 42
  43. 43. SELF CLEANING GLASS HOW DOES IT WORK? Glass is coated with a layer of nanocrystalline titanium dioxide (TiO2). The titanium dioxide reacts to the ultraviolet (UV) component of sunlight causing a gradual break down and loosening of dirt. This is known as the ‘photocatalytic’ stage The reaction also causes the glass surface to become super hydrophilic. This forces water to spread across the surface like a sheet, rather than beading, thereby washing away the loosened debris on the surface of The glass as it falls. This is the ‘hydrophilic’ stage.
  44. 44. APPLYING A MONOLAYER TO GLASS GLASS NANO COATINGS OptiView Anti-reflective glass made by Australian company Pilkington. Switchable glass changes from transparent to opaque. A nano-layer of a rod-like particle suspension is placed between two layers of glass. Under normal conditions, the suspended particles are arranged in random orientations and tend to absorb light, so that the glass panel looks frosted or opaque. But when a voltage is applied, the suspended particles align and let light pass, turning the glass clear. SWITCHABLE GLASS
  45. 45. CONCLUSION Glass is one of the most versatile and most fascinating materials Their uniqueness in physical, optical, thermal, mechanical and chemical properties offer an almost unlimited range of applications. Ultrasonic system has been employed to characterize their elastic properties. Extensive series of investigation using borate, phosphate and tellurite based glasses have been carried out to study the effect of certain oxides into those glass formers in terms of physical properties such as density, molar volumes and elasticity.

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