Table Of ContentCORROSION
OF
GLASS
David E. Clark
Visiting Assistant Professor, Department of Materiais Science and Engineering,
Ceramics Division, University of Florida, Gainesville, Florida 32611
Cario G. Pantano, Jr.
Materiais Scientist, Research Institute, University of Dayton, Dayton, Ohio 45469
Larry L. Hench
Professor and Head of Ceramics Division, Department of Materiais Science
and Engineering, University of Florida, Gainesville, Florida 32611
I
Published by Division of
Books for lndustry Magazines for Industry, Inc.
and 777 Third Avenue
The Glass lndustry New York, N.Y. 10017
Acknowledgements
The authors gratefully acknowledge the contributions of faculty, staff, and
students in the Ceramics Division of the Materiais Science and Engineering
Department of the University of Florida. ln particular, they wish to thank
M. F. Dilmore, E. C. Ethridge, and D. M. Sanders for their assistance in
data evaluation and interpretation. The authors also appreciate the assistance
with glass formulas and samples provided by Anchor Hocking and Brock
way Glass companies.
iii
library of Congress No. 79-50921
Copyright 1979 Magazines for lndustry, lnc.
Preface
Commercial glasses typically possess such excellent chemical durability that the non-specialist takes for granted
that glass does not corrode. Haven't museum specimens survived for thousands of years? Don't glass bottles and
windows serve their purposes without noticeable deterioration for their projected lifetimes? Isn't glass the container of
choice for ali sorts of chemicals and biologicals found in laboratories?
So generally satisfactory is the weathering and chemical behavior of glass that the positive term "chemical
durability" is generally applied instead of the more general term "corrosion". Nevertheless, glasses do corrode.
Study of the corrosion of glasses in service and in the laboratory has formed a significant portion of the efforts and the
literature of glass technology. Because of the generally slow rates at which notable corrosion occurs and because of
the thin surface layers which normally undergo alterations, researchers on corrosion of glasses and its measurement
have until recently worked under handicaps. To demonstrate by macromethods that corrosion is taking place requires
accelerated tests which often have been found not to correlate with behavior in service.
This dilemma has been resolved by the revolution in instrumentation for the analysis of the chemical and structural
changes in surfaces, on size scales down to atomic thicknesses. Such instruments, based on modem electronics, have
appeared in cascading numbers and increasing sophistication and resolution during the last dozen years or so.
Professor Larry Hench and his succession of graduate students at University of Florida have provided leadership in
the application of many such modem instruments to a range of investigations on the corrosion behavior of a variety of
glass and glass-ceramic compositions, configurations, and applications. This book represents a pioneering effort in
assessing the utilities of various instruments for following surface reactions in commercial glass compositions, and in
interpretations of chemical and physical changes accompanying varied conditions for corrosion of glasses.
Both makers and users of glasses owe gratitude to these authors for leadership in providing new insights and data
on what happens when glasses are corroded. It is my belief that publication of this book signifies a new era in the
measurement, understanding, and control of the chemical properties of commercial glasses.
Alexis G. Pincus
Technical Editor,
The Glass Industry
v
Table of Contents
Page
Preface .................................................... v
List of Figures ............................................ viii
List of Tables ............................................. xii
General Review of Corrosion and
Weathering of Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Analytical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Solution Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Infrared Reflection Spectroscopy (IRRS) ................... ll
Electron Microprobe Analysis (EMP) ..................... 13
Auger Electron Spectroscopy (AES) ...................... 15
Scanning Electron Microscopy/Energy Dispersive
X-ray Analysis (SEM/EXDA) ........................... 19
Summary ............................................ 21
3 Corrosion of Glass by Aqueous Solutions . . . . . . . . . . . . . . . . . 22
Effects of Glass Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Effects of Additives .................................... 29
Effects of Temperature ................................. 32
Effects of Corrosion Solution Replenishment ............... 35
p H Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Effects of Glass Surface Area to Solution Volume Ratio ...... 37
4 Weathering .......................................... 40
Overview ............................................ 40
Types of Weathering ................................... 40
Origin of Characteristic Surface Profile .................... 42
Surface Changes in Type l Weathering .................... 45
Surface Changes in Type 2 Weathering .................... 47
Effects of Surface Separation on Weathering ................ 49
Effects of S0 Treatment on Weathering ................... 51
2
Compositional Effects on Weathering . . . . . . . . . . . . . . . . . . . . . 52
vi i
5 Effects of Commerdal Fabrication on Glass ..... 55
Glass Surface .............................. 55
Thennal History ...................................... 55
Surface Chemical Reactions ............................. 56
Commercial Glass Containers ............................ 57
Untreated Surfaces ..................................... 58
Sulfur-Treated Surfaces ................................. 58
Fluorine-Treated Surfaces ............................... 60
6 Summary ............................................ 64
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Subject Index .............................................. 72
Author Index .............................................. 74
v iii
List of Figures
Page
1. Mechanisms of glass corrosion for a soda-silica glass . . . . . . . . 2
2. Typical exposure conditions encountered for glasses . . . . . . . . . 5
3. Sampling depths for various glass durability analysis tech-
niques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Static and dynamic corrosion conditions for glass powders and
bulk glass (planar) surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. V arious methods for evaluating extent of glass corrosion . . . . . 1O
6. SEM of corroded glass surface showing total dissolution (pit
ting) occurring in the scratches, 100°C-12 hours, SNV = 0.77
cm-1 (6000x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7. Schematic for double beam IRRS setup with a) a mirror as
reference standard, and b) a freshly abraded glass as a refer-
ence standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8. Infrared spectra for a freshly abraded (f.a.) glass and the sarne
glass corroded for various times . . . . . . . . . . . . . . . . . . . . . . . . . 12
9. Three techniques illustrating glass surface roughness for
specimens polished with 120 grit and 600 grit Si C paper . . . . . 13
10. Infrared spectra for severa! Na20-Ca0-Si02 glasses . . . . . . . . . 13
11. S peak position and glass surface composition as function of
corrosion time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
12. Na X-ray intensity as a function of electron beam impingement
time for various sample velocities using a 100~-tm beam diame-
ter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
13. Na X-ray intensity as a function of corrosion time for a 20
mole% Na20-10 mole% Ca0-70 mole% Si02 glass . . . . . . . . . 14
14. AES-ion milling system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
15. AES spectra for a multicomponent glass illustrating the effect
of temperature upon the ''measured'' composition . . . . . . . . . . 17
16. Effect of irradiation time and temperature upon the sodium
Auger signal from a soda-lime-sílica glass . . . . . . . . . . . . . . . . . 17
17. Schematic description of simultaneous AES analysis and inert
gas sputtering for obtaining in-depth composition profiles . . . . . 18
18. AES peak-to-peak heights vs. ion-milling time for inside sur-
face of a soda-lime-silica glass container . . . . . . . . . . . . . . . . . . 18
ix
19. Infrared reflection spectra for two corroded glasses. a) 20
mole% Na20-80 mole% Si02• b) 20 mole% Na20-10 mole%
Ca0-70 mole% Si02 • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 24
20. Infrared reflection spectra for the later stage of corrosion for
the 20 Na 0-l0 Ca0-70 Si0 glass . . . . . . . . . . . . . . . . . . . . . . 24
2 2
21. SEM's of corroded glass surfaces: (a) 20 Na20-80 Si02, 12h
l000 C (lOOOx), (b) 20 Na20-10 Ca0-70 Si02, 9d-l00°C
(1000x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
22. Infrared reflection spectra for freshly abraded and corroded 10
Na 0-10 Ca0-80 Si0 glass............................ 25
2 2
23. Infrared reflection spectra for freshly abraded and corroded 10
Na 0-20 Ca0-70 Si0 glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2 2
24. Infrared reflection spectra for freshly abraded and corroded 20
Na 0-20 Ca0-60 Si0 glass............................ 26
2 2
25. Infrared reflection spectra for freshly abraded and corroded 30
Na 0-10 Ca0-60 Si0 glass............................ 26
2 2
26. SEM of 30-10-60 glass corroded 12 h-100°C. (55x) . . . . . . . . . 28
27. Infrared reflection spectra for freshly abraded: A. 14% Na 0-
2
commercial glass. B. 14% Na 0-10 Ca0-76% Si0 glass. C.
2 2
14% Na 0-86% Si0 glass :. . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2 2
28. Infrared spectra for corroded 14% Na 0-86% Si0 glasses . . . 30
2 2
29. Infrared spectra for corroded 14% Na 0-10% Ca0-76% Si0
2 2
glasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
30. Infrared spectra for corroded 14% Na 0 commercial glasses . . 30
2
31. Na X-ray intensity as a function of corrosion time for three
glasses containing equivalem Na 0 . . . . . . . . . . . . . . . . . . . . . . 31
2
32. AES spectra for commercial soda-lime-silica glass as received
and after reaction in pure water . . . . . . . . . . . . . . . . . . . . . . . . . . 33
33. Depth compositional profiles for commercial soda-lime-sílica
glass surface after reaction in pure water at 37°C . . . . . . . . . . . . 34
34. Depth compositional profiles for commercial soda-lime-sílica
glass surface after reaction in pure water at 121.5° C . . . . . . . . 34
35. Comparison of depth profiles for soda-lime-silica glass after
reaction in pure water at 121.5°C before and after solution
replenishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
36. Comparison of depth profiles for soda-lime-silica glass after
reaction in aqueous solution of different pH . . . . . . . . . . . . . . . . 37
37. SEM of -45+60 mesh particle before corrosion illustrating
the presence of very fine powders on the surface. (2000x) . . . . 38
38. SEM of -45+60 mesh particle after corroding for 1d, 100°C,
SNV = 7.7 cm-1 (5100x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
39. Bulk solution pH as a function of corrosion time for severa!
particle size distributions and SNV ratios . . . . . . . . . . . . . . . . . 39
40. AES spectra for the inside surface of a commercial soda-
lime-sílica glass container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
41. AES peak-to-peak heights vs. ion-milling time for inside sur-
face of a soda-lime-silica glass container. . . . . . . . . . . . . . . . . . . 42
42. Depth compositional profiles for inside container surface, as
cast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
X
43. Changes in the surlace composition of soda-lime-sílica
during exposure to different environments . . . . . . . . . . . . . . . . . 43
44. Depth compositional profiles for soda-lime-silica glass surlace
aged 45 hours in a vacuum of 10-8 torr at room temperature.. . 43
45. Depth compositional profiles for soda-lime-silica glass surlace
after 5 minute reaction with air at room temperature . . . . . . . . . 44
46. Depth compositional profiles for soda-lime-silica glass surlace
after 60 minute reaction with air at room temperature ~ . . . . . . . 44
4 7. SIMS depth compositional prof ile of an ordinary glass slide . . . 44
48. lnfrared spectra of commercial glass for Type 1 weathering at
100°C-100 percent r. h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
49. Infrared spectra of commercial glass for Type 1 weathering at
50°C-100 percent r.h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
50. SEM's of Type 1 weathered commercial glass: (a) Type 1.
100°C-100 percent r. h., 1 day (620x), (b) Type 1, 100°C-100
percent r. h., 10 days (1200x) . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
51. Electron microprobe (EMP) X-ray intensities as a function of
exposure time for weathered commercial glass . . . . . . . . . . . . . . 46
52. lnfrared spectra of commercial glass for Type 2 weathering at
100°C-100 percent r.h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
53. Infrared spectra of commercial glass for Type 2 weathering at
50°C-100 percent r.h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
54. Infrared spectra of commercial glass for Type 2 weathering at
25°C-100 percent r.h. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
55. (a) SEM of Type 2 weathered commercial glass at 100° C-100
percent r.h. 20 days (1300x), (b) EDXA of a particle, and (c)
EDXA of an area adjacent to a particle . . . . . . . . . . . . . . . . . . . 48
56. Auger signals at various depths in Type 2 weathered commer-
cial glass, 100° C-100 percent r.h. for 15 days . . . . . . . . . . . . . 48
57. SEM's of weathered glass, (a) 20 days-50°C intimate contact
1500x pan, (b) 6 days-50°C infinite separation 2800x pan . . . . 49
58. Infrared reflection spectra for glass weathered while in intimate
contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
59. SEM of glass surlace weathered 5 days at 50°C-100 percent
r.h. separated from adjacent surface by 0.010"... . . . . . . . . . . . 50
60. Infrared reflection spectra for weathered glasses separated by
0.010" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
61. Infrared reflection spectra of untreated weathered glass ( # 11,
Table VI) and the sarne glass treated with S02 prior to weath-
ering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
62. Infrared spectra for weathered 20 Na20-10 Ca0-70 Si02 glass 53
63. Infrared spectra for weathered 10 Na20-10 Ca0-80 Si02 glass 53
64. Infrared spectra for weathered 10 Na20-20 Ca0-70 Si02 glass 53
65. Infrared spectra for weathered 30 Na20-10 Ca0-60 Si02 glass 53
66. Infrared spectra for weathered 20 Na20-20 Ca0-60 Si02 glass 53
67. Surface Na 0 concentration as a function of the square root of
corrosion ti2me for weathered glass as determined by IRRS . . . . 54
68. Depth compositional profile of untreated glass surface (glass
# 10, Table VI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
xi
69. Depth compositional profile of untreated glass surface afrer
subjection to the ASTM durability test . . . . . . . . . . . . . . . . . . . . 58
70. Auger spectra of untreated surface (upper) and sulfur-treated
surface, as-received (lower) . . . . . . . . . . . . . . . . . .. . . . . . . . . . . 59
71. SEM micrograph of sulfur treatment bloom ( ll,500x) . . . . . . . 59
72. Auger spectra of untreated surface (upper) and sulfur-treated
surface after rinsing in water (lower) . . . . . . . . . . . . . . . . . . . . . 59
73. Depth compositional proflle of sulfur-treated surface after rins-
ing in water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
74. Spectrum of the fluorine-treated surface in the as-received
condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
75. AES spectra of a fluorine-treated surface afrer rinsing in water 61
76. Depth compositional proflle for a fluorine-treated surface afrer
rinsing in water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
77. Depth compositional proflle for a fluorine-treated surface afrer
the AS TM durability test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
78. AES spectra of a glass etched in 5% HF . . . . . . . . . . . . . . . . . . 62
79. Schematic comparing static aqueous corrosion and weathering . 65
80. Schematic of plausible corrosion mechanisms . . . . . . . . . . . . . . 66
81. Five types of glass surfaces produced during corrosion . . . . . . . 66
82. Schematic of a depth compositional profile for a Type III glass
surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
83. SIMS depth compositional profile for a soda-lime-silica glass
both before and after exposure to citric acid. . . . . . . . . . . . . . . . 67
xii
