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Novel halide glasses based on systems of LiX (X = Cl, Br, I)
214
Journal of Non-Crystalline Solids 122 (1990) 214-215 North-Holland
LETTER TO THE EDITOR
NOVEL HALIDE GLASSES BASED ON SYSTEMS OF LiX (X-- CI, Br, I) Kohei KADONO, Katsura MITANI, Kenichi KINUGAWA
and Hiroshi TANAKA
Government Industrial Research Institute of Osaka, Midorigaoka, lkeda, Osaka 563, Japan
Received 23 February 1990 Revised manuscript received 24 April 1990
New halide glasses have been obtained in systems of LiX-KX-CsX-BaX 2 (X = C1, Br, I) where the main component is LiX. The glasses first discovered are those which contain only alkali halides and alkaline earth halides. Glass transition and crystallization temperatures were in the range of 40-80 °C and 65-105 o C, respectively. The IR cut-off wavelength is beyond 10 ~m. These glasses have high ionic conductivity, e.g., for the LiI-based glass, 5.8 × 10 -7 S/cm at 25 o C.
H a l i d e glasses o t h e r t h a n the fluoride are superior in m i d d l e a n d far i n f r a r e d t r a n s m i t t i n g p r o p e r ties to fluoride glasses [1]. Several glass f o r m i n g systems have b e e n r e p o r t e d [1]; however glass f o r m a t i o n is limited to a few k i n d s of halides, e.g., zinc a n d c a d m i u m halides a n d silver i o d i d e [2-7]. I n the p r e s e n t Letter, glass f o r m a t i o n in new h a l i d e systems a n d some p r o p e r t i e s of the glasses are r e p o r t e d . T h e glasses are b a s e d on l i t h i u m halides a n d c o n t a i n only o t h e r alkali halides a n d alkaline e a r t h halides as glass modifiers. T h e s e glasses are the first ones k n o w n in which the Li + ions a p p e a r to constitute the glass f o r m e r even t h o u g h Li + is k n o w n to b e a c o m p o n e n t of m a n y fast ion c o n d u c t i n g systems. R e a g e n t g r a d e a n h y d r o u s halides used for glass p r e p a r a t i o n were d r i e d at elevated t e m p e r a t u r e s in
v a c u o for 2 - 3 h. B a t c h m i x t u r e s of 3 g with a p p r o p r i a t e c o m p o s i t i o n s of halides were m e l t e d in a silica c r u c i b l e at 4 5 0 - 5 5 0 ° C for 15 min. T h e melts were p o u r e d on a b r a s s p l a t e which was c o o l e d at a b o u t 0 ° C a n d p r e s s e d with a second plate. G l a s s f o r m a t i o n was j u d g e d b y the transp a r e n c y of the s a m p l e s a n d was c o n f i r m e d b y X - r a y d i f f r a c t o m e t r y for s o m e samples. T h e prep a r a t i o n was c a r r i e d o u t in a glove b o x filled with n i t r o g e n in which the i m p u r i t y w a t e r was less t h a n 5 p p m . C h a r a c t e r i s t i c t e m p e r a t u r e s were m e a s u r e d b y D S C at a h e a t i n g r a t e of 10 K / m i n u n d e r d r y n i t r o g e n flow. I o n i c c o n d u c t i v i t i e s of the glasses were o b t a i n e d b y c o m p l e x i m p e d a n c e m e a s u r e m e n t s using silver p a i n t o n b o t h sides of the s a m p l e p l a t e s as electrodes. G l a s s f o r m a t i o n was e x a m i n e d m a i n l y for f o u r - c o m p o n e n t systems, L i X - K X - C s X - B a X 2 with o n l y one k i n d o f h a l i d e i o n where X = C1, Br or I.
Table 1 Characteristic temperatures of LiX-based glasses Composition (mol%)
Tg (°C)
Te (°C)
TI (°C)
Table 2 Ionic conductivity of LiX-based glasses
55LiC1-32KC1- 8CsCI-5BaC12 50LiC1- 36KC1-9CsC1-5BaCI 2
61 74
96 102
324 321
Composition (mol%)
55LiBr-20KBr-20CsBr-5BaBr2 55LiBr- 32KBr-8CsBr-5BaC12
52 44
79 68
242 300
Ionic conductivity at 25°C (S/cm)
55LiI-8KI-32CsI-5BaI2 50LiI-9KI-36CsI-5BaI2
40 50
68 73
212 208
55LiC1-32KCI-8CsC1- 5BaCI 2 55LiBr-20KBr-20CsBr-3.5BaBr/-1.5CaBrz 55LiI-8KI-32CsI-5BaI 2
5.3)<10 -9 2.6× 10 -s 5.8×10 -7
0022-3093/90/$03.50 © 1990 - Elsevier Science Publishers B.V. (North-Holland)
K. Kadono et aL / Novel halide glasses
BaCl.2
20
40
60
80
20
40 60 Bal 2
80
-4()-- -60 (mol%)
80
were 4, 1 and 1 / 4 for chloride, bromide and iodide systems, respectively. Replacement of a small amount of BaX 2 by C a X 2 made vitrification easier. On the other hand, glass formation was difficult for mixed halide systems. The glasses are sensitive to moisture and atmospheric exposure caused surface crystallization. In table I characteristic temperatures of several glasses are listed. These temperatures decrease in order: chloride, bromide and iodide, which is consistent with the order of melting point of the lithium halides: LiC1, 605°C; LiBr, 550°C; LiI, 449°C. Figure 2 shows an example of the IR spectra of the LiCl-based glasses. Absorption bands at around 3400 cm' and 1630 cm -1 are due to hydroxo group and H20. The cut-off wavelength is beyond 10 rtm in this glass and shifts to longer wavelength for the LiI-based glass. Preliminary measurements of ionic conductivity of these glasses were carried out and the results are listed in table 2. Spectroscopy and diffraction measurements for the investigation of the glass structure are in progress in our laboratory.
(KCt/CsCl.~)
( KBr/CsBr =1)
o/ 20
(Kl/Csl =1/4)
Fig. 1. Glass-forming regions of LiX-based systems: ©, glass; ~ , glass partly crystallized; t , crystal.
Figure 1 shows the glass-forming regions. Glasses are obtained in very limited compositions: 50-55 mol% LiX and 5 mol% BaX 2. The most appropriate molar ratios, K X / C s X , to vitrification
2.5
Wavelength 5
3 I
(pm)
I
10
20
I
I
r= ttO 1--
I
4000
3000
I
I
2000 1500 1000 Wavenumber (cm -1 )
500
Fig. 2. IR spectra of the 55LiCI-35KC1-7.5BaC12-2.5CaC12
glass.
215
The authors are grateful to Mr Masaru Yamashita for the measurements of ionic conductivity of the glasses.
References [1] For example: (a) M. Poulain, J. Non-Cryst. Solids 56 (1983) 1; (b) J. Lucas, J. Non-Cryst Solids 89 (1986) 83; (c) Ma Fu Ding, John Lau and J.D. Mackenzie, J. Non-Cryst Solids 89 (1986) 538. [2] K. Kadono, A. Yasuyoshi, T. Tarumi, H. Nakamichi, H. Tanaka and M. Nogami, Mater. Res. Bull. 23 (1988) 785. [3] M. Poulain, M. Matecki, J.-L. Mouric and M. Poulain, Mater. Res. Bull. 18 (1983) 631. [4] E.I. Cooper and C.A. AngeU, J. Non-Cryst. Solids 56 (1983) 75. [5] M. Matecki, M. Poulain and M. Poulain, J. Non-Cryst. Solids 56 (1983) 81. [6] J. Nishii, Y. Kaite and T. Yamagishi, J. Non-Cryst. Solids 74 (1985) 411. [7] B. PetrovA, M. Frumar, E. StrhnksA and I. Hlo~nek, J. Mater. Sci. 24 (1989) 4555.
Journal of Non-Crystalline Solids 122 (1990) 214-215 North-Holland
LETTER TO THE EDITOR
NOVEL HALIDE GLASSES BASED ON SYSTEMS OF LiX (X-- CI, Br, I) Kohei KADONO, Katsura MITANI, Kenichi KINUGAWA
and Hiroshi TANAKA
Government Industrial Research Institute of Osaka, Midorigaoka, lkeda, Osaka 563, Japan
Received 23 February 1990 Revised manuscript received 24 April 1990
New halide glasses have been obtained in systems of LiX-KX-CsX-BaX 2 (X = C1, Br, I) where the main component is LiX. The glasses first discovered are those which contain only alkali halides and alkaline earth halides. Glass transition and crystallization temperatures were in the range of 40-80 °C and 65-105 o C, respectively. The IR cut-off wavelength is beyond 10 ~m. These glasses have high ionic conductivity, e.g., for the LiI-based glass, 5.8 × 10 -7 S/cm at 25 o C.
H a l i d e glasses o t h e r t h a n the fluoride are superior in m i d d l e a n d far i n f r a r e d t r a n s m i t t i n g p r o p e r ties to fluoride glasses [1]. Several glass f o r m i n g systems have b e e n r e p o r t e d [1]; however glass f o r m a t i o n is limited to a few k i n d s of halides, e.g., zinc a n d c a d m i u m halides a n d silver i o d i d e [2-7]. I n the p r e s e n t Letter, glass f o r m a t i o n in new h a l i d e systems a n d some p r o p e r t i e s of the glasses are r e p o r t e d . T h e glasses are b a s e d on l i t h i u m halides a n d c o n t a i n only o t h e r alkali halides a n d alkaline e a r t h halides as glass modifiers. T h e s e glasses are the first ones k n o w n in which the Li + ions a p p e a r to constitute the glass f o r m e r even t h o u g h Li + is k n o w n to b e a c o m p o n e n t of m a n y fast ion c o n d u c t i n g systems. R e a g e n t g r a d e a n h y d r o u s halides used for glass p r e p a r a t i o n were d r i e d at elevated t e m p e r a t u r e s in
v a c u o for 2 - 3 h. B a t c h m i x t u r e s of 3 g with a p p r o p r i a t e c o m p o s i t i o n s of halides were m e l t e d in a silica c r u c i b l e at 4 5 0 - 5 5 0 ° C for 15 min. T h e melts were p o u r e d on a b r a s s p l a t e which was c o o l e d at a b o u t 0 ° C a n d p r e s s e d with a second plate. G l a s s f o r m a t i o n was j u d g e d b y the transp a r e n c y of the s a m p l e s a n d was c o n f i r m e d b y X - r a y d i f f r a c t o m e t r y for s o m e samples. T h e prep a r a t i o n was c a r r i e d o u t in a glove b o x filled with n i t r o g e n in which the i m p u r i t y w a t e r was less t h a n 5 p p m . C h a r a c t e r i s t i c t e m p e r a t u r e s were m e a s u r e d b y D S C at a h e a t i n g r a t e of 10 K / m i n u n d e r d r y n i t r o g e n flow. I o n i c c o n d u c t i v i t i e s of the glasses were o b t a i n e d b y c o m p l e x i m p e d a n c e m e a s u r e m e n t s using silver p a i n t o n b o t h sides of the s a m p l e p l a t e s as electrodes. G l a s s f o r m a t i o n was e x a m i n e d m a i n l y for f o u r - c o m p o n e n t systems, L i X - K X - C s X - B a X 2 with o n l y one k i n d o f h a l i d e i o n where X = C1, Br or I.
Table 1 Characteristic temperatures of LiX-based glasses Composition (mol%)
Tg (°C)
Te (°C)
TI (°C)
Table 2 Ionic conductivity of LiX-based glasses
55LiC1-32KC1- 8CsCI-5BaC12 50LiC1- 36KC1-9CsC1-5BaCI 2
61 74
96 102
324 321
Composition (mol%)
55LiBr-20KBr-20CsBr-5BaBr2 55LiBr- 32KBr-8CsBr-5BaC12
52 44
79 68
242 300
Ionic conductivity at 25°C (S/cm)
55LiI-8KI-32CsI-5BaI2 50LiI-9KI-36CsI-5BaI2
40 50
68 73
212 208
55LiC1-32KCI-8CsC1- 5BaCI 2 55LiBr-20KBr-20CsBr-3.5BaBr/-1.5CaBrz 55LiI-8KI-32CsI-5BaI 2
5.3)<10 -9 2.6× 10 -s 5.8×10 -7
0022-3093/90/$03.50 © 1990 - Elsevier Science Publishers B.V. (North-Holland)
K. Kadono et aL / Novel halide glasses
BaCl.2
20
40
60
80
20
40 60 Bal 2
80
-4()-- -60 (mol%)
80
were 4, 1 and 1 / 4 for chloride, bromide and iodide systems, respectively. Replacement of a small amount of BaX 2 by C a X 2 made vitrification easier. On the other hand, glass formation was difficult for mixed halide systems. The glasses are sensitive to moisture and atmospheric exposure caused surface crystallization. In table I characteristic temperatures of several glasses are listed. These temperatures decrease in order: chloride, bromide and iodide, which is consistent with the order of melting point of the lithium halides: LiC1, 605°C; LiBr, 550°C; LiI, 449°C. Figure 2 shows an example of the IR spectra of the LiCl-based glasses. Absorption bands at around 3400 cm' and 1630 cm -1 are due to hydroxo group and H20. The cut-off wavelength is beyond 10 rtm in this glass and shifts to longer wavelength for the LiI-based glass. Preliminary measurements of ionic conductivity of these glasses were carried out and the results are listed in table 2. Spectroscopy and diffraction measurements for the investigation of the glass structure are in progress in our laboratory.
(KCt/CsCl.~)
( KBr/CsBr =1)
o/ 20
(Kl/Csl =1/4)
Fig. 1. Glass-forming regions of LiX-based systems: ©, glass; ~ , glass partly crystallized; t , crystal.
Figure 1 shows the glass-forming regions. Glasses are obtained in very limited compositions: 50-55 mol% LiX and 5 mol% BaX 2. The most appropriate molar ratios, K X / C s X , to vitrification
2.5
Wavelength 5
3 I
(pm)
I
10
20
I
I
r= ttO 1--
I
4000
3000
I
I
2000 1500 1000 Wavenumber (cm -1 )
500
Fig. 2. IR spectra of the 55LiCI-35KC1-7.5BaC12-2.5CaC12
glass.
215
The authors are grateful to Mr Masaru Yamashita for the measurements of ionic conductivity of the glasses.
References [1] For example: (a) M. Poulain, J. Non-Cryst. Solids 56 (1983) 1; (b) J. Lucas, J. Non-Cryst Solids 89 (1986) 83; (c) Ma Fu Ding, John Lau and J.D. Mackenzie, J. Non-Cryst Solids 89 (1986) 538. [2] K. Kadono, A. Yasuyoshi, T. Tarumi, H. Nakamichi, H. Tanaka and M. Nogami, Mater. Res. Bull. 23 (1988) 785. [3] M. Poulain, M. Matecki, J.-L. Mouric and M. Poulain, Mater. Res. Bull. 18 (1983) 631. [4] E.I. Cooper and C.A. AngeU, J. Non-Cryst. Solids 56 (1983) 75. [5] M. Matecki, M. Poulain and M. Poulain, J. Non-Cryst. Solids 56 (1983) 81. [6] J. Nishii, Y. Kaite and T. Yamagishi, J. Non-Cryst. Solids 74 (1985) 411. [7] B. PetrovA, M. Frumar, E. StrhnksA and I. Hlo~nek, J. Mater. Sci. 24 (1989) 4555.