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Ionic conductivities of rapidly quenched AgI-Ag2O-B2O3 glasses containing large amounts of AgI
SOLID STATE ELSEYIER
loNlc5
Solid State Ionics 86-88 (1996) 491-495
Ionic conductivities of rapidly quenched AgI-Ag20-B,O, containing large amounts of AgI Toshiharu
Saito”, Naoto Torata, Masahiro Tatsumisago,
Tsutomu
glasses
Minami
Department of Applied Materials Science, Osaka Prefecture University, Sakai, Osaka 593, Japan
Abstract Ionic conductivities of twin-roller rapidly quenched AgI-Ag,O-B,O, glasses (Ag,O/B,O, = 3) were measured in a wide temperature range between 200 and 400 K. The activation energy E, for conduction of the glass with 50 mol% AgI was not changed in the whole temperature range. However, the E, values of the glasses with 60 and 70 mol% AgI were largely changed at around 240 K; the E, values below 240 K were larger than those above 240 K. The glasses containing 60-80 mol% AgI had an inhomogeneous morphology. These inhomogeneities in rapidly quenched AgI-Ag,O-B,O, containing large amounts of AgI were supposed to be closely related to the change in E, at around 240 K. Keywords: Ion conductivity;
Glasses;
Activation
energy
1. Introduction Superionic conductor a-AgI, which is thermodynamically stable only above 420 K, was successfully frozen in AgI-Ag,O-B,O, glasses at room temperature by a twin-roller rapid quenching technique [ 1,2]. We have already reported the electrical properties of the a-AgI-frozen composites. Such glass-crystallite composites exhibited extremely high ionic conductivities of about 10-l S cm-’ at room temperature and quite low activation energies for conduction E, of about 15 kJ mol-’ in the temperature range higher than room temperature [3], resulting from a-AgI crystallites (- 30 nm in diameter) homogeneously dispersed in superionic glass matrices [4,5]. We also measured the ionic conductivities of the cu-AgI-frozen 82AgI * 13SAg,O * 4SB,O, and 82AgI. 9Ag,O * 9B,O, (in mol%) *Correspondingauthor. 0167-2738/96/$15.00 Copyright PII SO167-2738(96)00180-4
01996
glasses
composites at temperatures below room temperature; the temperature dependence of conductivity of these composites was non-Arrhenius and the composites had larger E, values at lower temperatures [6,7]. In contrast to the result mentioned above, the temperature dependence of conductivities for AgIAg,O-B,O, glasses within the glass-forming region obtained by usual metal-plate quenching was reported to be the perfect Arrhenius type variation in the wide temperature range between 120 K and their glass transition temperature (T,) [8]. In the orthoborate glassy system, the glass formation limit by the metal-plate press quenching was around 65 mol% AgI [9], but the twin-roller rapid quenching extended the glass formation limit up to 80 mol% AgI. The orthoborate glasses containing about 75 mol% AgI, prepared by the twin-roller rapid quenching, were found to have inhomogeneities in their microstructures, although only halo patterns were observed in the X-ray diffraction of these glasses [lo]. It is of
Elsevier Science B.V. All rights reserved
492
T. S&o
rt d.
I Solid State lonics
great interest to study the temperature dependence of conductivities for the orthoborate glasses containing large amounts of AgI (65 < mol% AgI < 80) prepared by the twin-roller quenching, because the electrical properties of the glasses containing smaller amounts of AgI (mol% AgI < 65) were significantly different from those of the cu-AgI composites with 80-82 mol% AgI. In the present study, we measured the ionic conductivities of the twin-roller rapidly quenched AgI-Ag,O-B,O, (Ag,O/B,O, = 3; orthoborate composition) glasses containing 50, 60 and 70 mol% AgI in the temperature range between 200 and 400 K. The microstructures of these glasses were also studied by a field-emission-type scanning electron microscopy (FE-SEM).
86-M’
(1996)
491-49-5
Temperaturei K
lo.”
2.5 Fig. I. Temperature
’ 3
3.5 4 4.5 lOOOK /T
5
dependence of conductivities
I 5.5 for the twin-
2. Experimental
roller quenched xAg1.
The starting materials for sample preparation were reagent grade chemicals, AgI, Ag,O and B,O,. Batches of the mixed materials were melted at 873 K for 30 min in a silica glass tube with one open end. The twin-roller quenching technique, the cooling rate of which was about 10’ - IO’ K SC’, was used for sample preparation; flake-like samples with a thickness of about 20 pm were obtained. The conductivity was measured for the flakes, on which two parallel gold electrodes were evaporated 2 mm apart. The measurements were carried out in dry nitrogen atmosphere using an impedance analyzer (HP 4192A) in the temperature range between 200 and 400 K. The microstructure of the twin-roller quenched samples was observed by a field-emission-type scanning electron microscope (FE-SEM, Hitachi S4500).
tivities of the glasses of x = 50, 60 and 70, respectively. The conductivities of the cY-AgI-frozen composite (X = 82), denoted by closed circles, is also shown for comparison. In a previous paper [3], we reported the temperature dependence of conductivities for the twin-roller quenched samples in this system in the temperature range between 298 and 500 K. In such a temperature range, the conductivities of the glasses of x = 60 and 70 and the conductivities of the a-AgI-frozen composite of x = 82 were increased with increasing temperature in the Arrhenius type variation. The slope of conductivity plots for the glass of x = 50 is hardly changed in the whole temperature range shown in Fig. 1. This result suggests that the orthoborate glass containing 50 mol% AgI, which can be prepared by usual metal-plate press quenching, exhibits an Arrhenius type variation in conductivity in the wide temperature range between 200 and 400 K. However, the slopes of conductivity plots for the glasses of x = 60 and 70 is slightly changed at around 250 K. The slope of conductivity plots for the composite of x = 82 becomes larger with decreasing temperature below about 260 K, as reported previously [6,7]. Fig. 2 shows the temperature dependence of activation energy E, for conduction of the twin-roller quenched xAgI . (100 - x)(0.75Ag,O. 0.25B,O,)
3. Results and discussion Fig. 1 shows the temperature dependence of conductivities for various twin-roller quenched glasses of the composition xAgI * ( 100 - x)(0.75Ag,O. 0.25B,O,) in mol%. All the conductivity data were measured during heating from 200 to 400 K. Open triangles, circles and squares denote the conduc-
(100- x)(0.75Agz0. O.ZSB,O,)
samples.
T. Saito et al. I Solid State Ionics 86-88 (1996) 491-495
40
493
I
-_ 30 i? 3 m lJJ 20
10 200
250
300 350 Temperature I K
dependence of activation Fig. 2. Temperature conduction for the twin-roller quenched x)(0.75Agz0 .0.2SB20,) samples.
400
energy E, for xAg1. (100-
glasses. These E, values at a given temperature were calculated from the slopes of three data points, including two subsequent points, shown in Fig. 1. The symbols of samples are the same as those denoted in Fig. 1. The E, values of x = 50 are around 35 kJ mall’ in the whole temperature range. On the other hand, a steep change in E, is observed in the glasses of x = 60 and 70 at around 240 K. The Ea values in the temperature ranges lower and higher than the temperature where the steep change is observed are almost constant, and the values in the low temperature range are larger than those in the high temperature range. The steep change in E, of the composite of x = 82 is also observed at around 260 K as reported previously [6,7]. Fig. 3 shows the photographs of FE-SEM crosssection for the twin-roller quenched xAg1 . ( 100 x)(0,75Ag,O. 0.25B,O,) samples; (a): x = 50, (b): x = 70, (c): x = 82 (in mol%). The glass (a), which could be prepared by usual metal-plate press quenching, is found to have a typical glassy homogeneous morphology. On the other hand, the glass (b), which could be prepared only by twin-roller rapid quenching, is found to have inhomogeneities; dispersed phases with several ten nanometers in diameter are observed to be present in the microstructure, although a halo pattern was observed in the X-ray diffraction of this sample. It was found from a detailed study of microstructures of these glasses that
Fig. 3. Photographs of FE-SEM cross-section for the twin-roller quenched xAgl (100- x)(0.75Ag,O. 0.25B,O,) samples; (a): x = 50, (b): x = 70, (c): x = 82 (in mol%).
494
T. Saito et al. I Solid State tonics 86-88
such dispersed phases were observed to be present in the glasses with 60-80 mol% AgI, in which only halo patterns were observed in their X-ray diffraction, and the amounts of these phases increased with increasing AgI content. A large number of fine particles were observed in the a-AgI-frozen composite (c); these fine particles are the cY-Agl crystallites dispersed in the AgI-based orthoborate glassy matrix [4,5]. The dispersed phases in Fig. 3b are similar in shape and in size to the dispersed particles of frozen a-AgI crystallites shown in Fig. 3c. Such dispersed phases in the glass shown in Fig. 3b are supposed to be the AgI-rich amorphous phases dispersed in a matrix glass. Many efforts have been devoted to clarify the relationships between the high ionic conductivity and structures of AgI-based superionic glasses. Several structural models have been proposed to account for the high ionic conductivity of these glasses. The diffusion path model [11,12] and/or the microcluster (microdomain) model [ 13-151 have been strongly supported as the explanation of high ionic conductivity and have been widely accepted. According to these models, the Ag+ ions migrate through pathways composed of I- ion polyhedra similar to the case of a-AgI or composed of cY-AgI-like microclusters. These models mean that the AgI-rich amorphous regions made up by a-AgI-like structures exist in the superionic glasses. Very recently, from the results of calorimetric study, Nakayama et al. suggested that regions of amorphous AgI aggregates began to appear within the tissues with increasing AgI content of superionic glasses [16]. In such AgI-rich amorphous regions, a number of mobile Ag+ ions surrounded only by Iions exist in the disordered state. In a low temperature range near the liquid nitrogen temperature, the positional rearrangement of Agf ions was observed as P-glass transition of superionic glasses containing large amounts of AgI [16]. From the structural point of view mentioned above, the dispersed phases shown in Fig. 3b are supposed to be the extremely large textures of amorphous AgI aggregates containing a large number of mobile Agf ions. Since the glass with 50 mol% Agl, in which the E, values did not change over the whole temperature range, had a homogeneous morphology, the dispersed phases in the
(1996) 491-495
glasses with 60-80 mol% AgI are presumed to strongly affect the steep change in E, at around 240 K, which is probably attributable to P-glass transition of AgI-Ag,O-B,O, glasses containing large amounts of AgI prepared by rapid quenching.
4. Conclusions The E, values of the glass with 50 mol% AgI were almost constant over the whole temperature range between 200 and 400 K. However, in the glasses with 60 and 70 mol% AgI, a steep change in E, was observed at around 240 K; the E, values below 240 K were larger than those above 240 K. Dispersed phases with several ten nanometers in diameter were observed to be present in the rapidly quenched AgIAg,O-B,O, glasses containing 60-80 mol% AgI. These inhomogeneities due to AgI-rich amorphous phase were supposed to strongly affect the steep change in E, at around 240 K, which was probably attributable to P-glass transition of AgI-Ag,OB,O, glasses containing large amounts of AgI prepared by rapid quenching.
Acknowledgments This work was partly supported by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture of Japan and also by the Proposal-Based Advanced Industrial Technology R&D Program from the New Energy and Industrial Technology Development Organization (NEDO).
References Ll1 M. Tatsumisago,
Y. Shinkuma (1991) 217. I21 M. Tatsumisago, T. Saito and (1991) 643. L31 T. Saito, M. Tatsumisago and 61 (1993) 285. 141 T. Saito, M. Tatsumisago and (1995) 10691. [51 T. Saito, M. Tatsumisago and 79 ( 1995) 279.
and T. Minami,
Nature 354
T. Minami, Chem. Express 6 T. Minami, Solid State Ionics T. Minami, J. Phys. Chem. 99 T. Minami, Solid State Ionics
T. Saito et al. I Solid State Ionics 86-88
[6] M. Tatsumisago,
17) [S] [9] [IO] [l I]
T. Saito, T. Minami, M. Hanaya and M. Oguni, J. Phys. Chem. 98 (1994) 2005. M. Tatsumisago, T. Saito and T. Minami, Solid State Ionics 70/71 (1994) 394. A. Magistris, G. Chiodelli and A. Schiraldi, Electrochim. Acta 24 (1979) 203. T. Minami, Y. Ikeda and M. Tanaka, J. Non-Cryst. Solids 52 (1982) 159. M. Tatsumisago, N. Torata, T. Saito and T. Minami, J. Non-Cryst. Sohds 196 (1996) 193. T. Minami, K. Imazawa and M. Tanaka, J. Non-Cryst. Solids 42 ( 1980) 469.
(1996)
491-495
495
[12] T. Minami, J. Non-Cryst. Solids 73 (1985) 273. [I31 J.P. Malugani, and R. Mercier, Solid State Ionics 13 (1984) 293.
[ 141 S. Muto, T. Suemoto, and M. Ishigame, Solid State Ionics 35 (1989) 307. [15] L. Borjesson, ( 1990) 702.
and W.S. Howels,
Solid State Ionics 40/41
[I61 M. Nakayama, M. Hanaya, A. Hatate and M. Oguni, Non-Cryst. Solids 172/ 174 (1994) 1252.
J.
loNlc5
Solid State Ionics 86-88 (1996) 491-495
Ionic conductivities of rapidly quenched AgI-Ag20-B,O, containing large amounts of AgI Toshiharu
Saito”, Naoto Torata, Masahiro Tatsumisago,
Tsutomu
glasses
Minami
Department of Applied Materials Science, Osaka Prefecture University, Sakai, Osaka 593, Japan
Abstract Ionic conductivities of twin-roller rapidly quenched AgI-Ag,O-B,O, glasses (Ag,O/B,O, = 3) were measured in a wide temperature range between 200 and 400 K. The activation energy E, for conduction of the glass with 50 mol% AgI was not changed in the whole temperature range. However, the E, values of the glasses with 60 and 70 mol% AgI were largely changed at around 240 K; the E, values below 240 K were larger than those above 240 K. The glasses containing 60-80 mol% AgI had an inhomogeneous morphology. These inhomogeneities in rapidly quenched AgI-Ag,O-B,O, containing large amounts of AgI were supposed to be closely related to the change in E, at around 240 K. Keywords: Ion conductivity;
Glasses;
Activation
energy
1. Introduction Superionic conductor a-AgI, which is thermodynamically stable only above 420 K, was successfully frozen in AgI-Ag,O-B,O, glasses at room temperature by a twin-roller rapid quenching technique [ 1,2]. We have already reported the electrical properties of the a-AgI-frozen composites. Such glass-crystallite composites exhibited extremely high ionic conductivities of about 10-l S cm-’ at room temperature and quite low activation energies for conduction E, of about 15 kJ mol-’ in the temperature range higher than room temperature [3], resulting from a-AgI crystallites (- 30 nm in diameter) homogeneously dispersed in superionic glass matrices [4,5]. We also measured the ionic conductivities of the cu-AgI-frozen 82AgI * 13SAg,O * 4SB,O, and 82AgI. 9Ag,O * 9B,O, (in mol%) *Correspondingauthor. 0167-2738/96/$15.00 Copyright PII SO167-2738(96)00180-4
01996
glasses
composites at temperatures below room temperature; the temperature dependence of conductivity of these composites was non-Arrhenius and the composites had larger E, values at lower temperatures [6,7]. In contrast to the result mentioned above, the temperature dependence of conductivities for AgIAg,O-B,O, glasses within the glass-forming region obtained by usual metal-plate quenching was reported to be the perfect Arrhenius type variation in the wide temperature range between 120 K and their glass transition temperature (T,) [8]. In the orthoborate glassy system, the glass formation limit by the metal-plate press quenching was around 65 mol% AgI [9], but the twin-roller rapid quenching extended the glass formation limit up to 80 mol% AgI. The orthoborate glasses containing about 75 mol% AgI, prepared by the twin-roller rapid quenching, were found to have inhomogeneities in their microstructures, although only halo patterns were observed in the X-ray diffraction of these glasses [lo]. It is of
Elsevier Science B.V. All rights reserved
492
T. S&o
rt d.
I Solid State lonics
great interest to study the temperature dependence of conductivities for the orthoborate glasses containing large amounts of AgI (65 < mol% AgI < 80) prepared by the twin-roller quenching, because the electrical properties of the glasses containing smaller amounts of AgI (mol% AgI < 65) were significantly different from those of the cu-AgI composites with 80-82 mol% AgI. In the present study, we measured the ionic conductivities of the twin-roller rapidly quenched AgI-Ag,O-B,O, (Ag,O/B,O, = 3; orthoborate composition) glasses containing 50, 60 and 70 mol% AgI in the temperature range between 200 and 400 K. The microstructures of these glasses were also studied by a field-emission-type scanning electron microscopy (FE-SEM).
86-M’
(1996)
491-49-5
Temperaturei K
lo.”
2.5 Fig. I. Temperature
’ 3
3.5 4 4.5 lOOOK /T
5
dependence of conductivities
I 5.5 for the twin-
2. Experimental
roller quenched xAg1.
The starting materials for sample preparation were reagent grade chemicals, AgI, Ag,O and B,O,. Batches of the mixed materials were melted at 873 K for 30 min in a silica glass tube with one open end. The twin-roller quenching technique, the cooling rate of which was about 10’ - IO’ K SC’, was used for sample preparation; flake-like samples with a thickness of about 20 pm were obtained. The conductivity was measured for the flakes, on which two parallel gold electrodes were evaporated 2 mm apart. The measurements were carried out in dry nitrogen atmosphere using an impedance analyzer (HP 4192A) in the temperature range between 200 and 400 K. The microstructure of the twin-roller quenched samples was observed by a field-emission-type scanning electron microscope (FE-SEM, Hitachi S4500).
tivities of the glasses of x = 50, 60 and 70, respectively. The conductivities of the cY-AgI-frozen composite (X = 82), denoted by closed circles, is also shown for comparison. In a previous paper [3], we reported the temperature dependence of conductivities for the twin-roller quenched samples in this system in the temperature range between 298 and 500 K. In such a temperature range, the conductivities of the glasses of x = 60 and 70 and the conductivities of the a-AgI-frozen composite of x = 82 were increased with increasing temperature in the Arrhenius type variation. The slope of conductivity plots for the glass of x = 50 is hardly changed in the whole temperature range shown in Fig. 1. This result suggests that the orthoborate glass containing 50 mol% AgI, which can be prepared by usual metal-plate press quenching, exhibits an Arrhenius type variation in conductivity in the wide temperature range between 200 and 400 K. However, the slopes of conductivity plots for the glasses of x = 60 and 70 is slightly changed at around 250 K. The slope of conductivity plots for the composite of x = 82 becomes larger with decreasing temperature below about 260 K, as reported previously [6,7]. Fig. 2 shows the temperature dependence of activation energy E, for conduction of the twin-roller quenched xAgI . (100 - x)(0.75Ag,O. 0.25B,O,)
3. Results and discussion Fig. 1 shows the temperature dependence of conductivities for various twin-roller quenched glasses of the composition xAgI * ( 100 - x)(0.75Ag,O. 0.25B,O,) in mol%. All the conductivity data were measured during heating from 200 to 400 K. Open triangles, circles and squares denote the conduc-
(100- x)(0.75Agz0. O.ZSB,O,)
samples.
T. Saito et al. I Solid State Ionics 86-88 (1996) 491-495
40
493
I
-_ 30 i? 3 m lJJ 20
10 200
250
300 350 Temperature I K
dependence of activation Fig. 2. Temperature conduction for the twin-roller quenched x)(0.75Agz0 .0.2SB20,) samples.
400
energy E, for xAg1. (100-
glasses. These E, values at a given temperature were calculated from the slopes of three data points, including two subsequent points, shown in Fig. 1. The symbols of samples are the same as those denoted in Fig. 1. The E, values of x = 50 are around 35 kJ mall’ in the whole temperature range. On the other hand, a steep change in E, is observed in the glasses of x = 60 and 70 at around 240 K. The Ea values in the temperature ranges lower and higher than the temperature where the steep change is observed are almost constant, and the values in the low temperature range are larger than those in the high temperature range. The steep change in E, of the composite of x = 82 is also observed at around 260 K as reported previously [6,7]. Fig. 3 shows the photographs of FE-SEM crosssection for the twin-roller quenched xAg1 . ( 100 x)(0,75Ag,O. 0.25B,O,) samples; (a): x = 50, (b): x = 70, (c): x = 82 (in mol%). The glass (a), which could be prepared by usual metal-plate press quenching, is found to have a typical glassy homogeneous morphology. On the other hand, the glass (b), which could be prepared only by twin-roller rapid quenching, is found to have inhomogeneities; dispersed phases with several ten nanometers in diameter are observed to be present in the microstructure, although a halo pattern was observed in the X-ray diffraction of this sample. It was found from a detailed study of microstructures of these glasses that
Fig. 3. Photographs of FE-SEM cross-section for the twin-roller quenched xAgl (100- x)(0.75Ag,O. 0.25B,O,) samples; (a): x = 50, (b): x = 70, (c): x = 82 (in mol%).
494
T. Saito et al. I Solid State tonics 86-88
such dispersed phases were observed to be present in the glasses with 60-80 mol% AgI, in which only halo patterns were observed in their X-ray diffraction, and the amounts of these phases increased with increasing AgI content. A large number of fine particles were observed in the a-AgI-frozen composite (c); these fine particles are the cY-Agl crystallites dispersed in the AgI-based orthoborate glassy matrix [4,5]. The dispersed phases in Fig. 3b are similar in shape and in size to the dispersed particles of frozen a-AgI crystallites shown in Fig. 3c. Such dispersed phases in the glass shown in Fig. 3b are supposed to be the AgI-rich amorphous phases dispersed in a matrix glass. Many efforts have been devoted to clarify the relationships between the high ionic conductivity and structures of AgI-based superionic glasses. Several structural models have been proposed to account for the high ionic conductivity of these glasses. The diffusion path model [11,12] and/or the microcluster (microdomain) model [ 13-151 have been strongly supported as the explanation of high ionic conductivity and have been widely accepted. According to these models, the Ag+ ions migrate through pathways composed of I- ion polyhedra similar to the case of a-AgI or composed of cY-AgI-like microclusters. These models mean that the AgI-rich amorphous regions made up by a-AgI-like structures exist in the superionic glasses. Very recently, from the results of calorimetric study, Nakayama et al. suggested that regions of amorphous AgI aggregates began to appear within the tissues with increasing AgI content of superionic glasses [16]. In such AgI-rich amorphous regions, a number of mobile Ag+ ions surrounded only by Iions exist in the disordered state. In a low temperature range near the liquid nitrogen temperature, the positional rearrangement of Agf ions was observed as P-glass transition of superionic glasses containing large amounts of AgI [16]. From the structural point of view mentioned above, the dispersed phases shown in Fig. 3b are supposed to be the extremely large textures of amorphous AgI aggregates containing a large number of mobile Agf ions. Since the glass with 50 mol% Agl, in which the E, values did not change over the whole temperature range, had a homogeneous morphology, the dispersed phases in the
(1996) 491-495
glasses with 60-80 mol% AgI are presumed to strongly affect the steep change in E, at around 240 K, which is probably attributable to P-glass transition of AgI-Ag,O-B,O, glasses containing large amounts of AgI prepared by rapid quenching.
4. Conclusions The E, values of the glass with 50 mol% AgI were almost constant over the whole temperature range between 200 and 400 K. However, in the glasses with 60 and 70 mol% AgI, a steep change in E, was observed at around 240 K; the E, values below 240 K were larger than those above 240 K. Dispersed phases with several ten nanometers in diameter were observed to be present in the rapidly quenched AgIAg,O-B,O, glasses containing 60-80 mol% AgI. These inhomogeneities due to AgI-rich amorphous phase were supposed to strongly affect the steep change in E, at around 240 K, which was probably attributable to P-glass transition of AgI-Ag,OB,O, glasses containing large amounts of AgI prepared by rapid quenching.
Acknowledgments This work was partly supported by a Grant-in-Aid from the Ministry of Education, Science, Sports and Culture of Japan and also by the Proposal-Based Advanced Industrial Technology R&D Program from the New Energy and Industrial Technology Development Organization (NEDO).
References Ll1 M. Tatsumisago,
Y. Shinkuma (1991) 217. I21 M. Tatsumisago, T. Saito and (1991) 643. L31 T. Saito, M. Tatsumisago and 61 (1993) 285. 141 T. Saito, M. Tatsumisago and (1995) 10691. [51 T. Saito, M. Tatsumisago and 79 ( 1995) 279.
and T. Minami,
Nature 354
T. Minami, Chem. Express 6 T. Minami, Solid State Ionics T. Minami, J. Phys. Chem. 99 T. Minami, Solid State Ionics
T. Saito et al. I Solid State Ionics 86-88
[6] M. Tatsumisago,
17) [S] [9] [IO] [l I]
T. Saito, T. Minami, M. Hanaya and M. Oguni, J. Phys. Chem. 98 (1994) 2005. M. Tatsumisago, T. Saito and T. Minami, Solid State Ionics 70/71 (1994) 394. A. Magistris, G. Chiodelli and A. Schiraldi, Electrochim. Acta 24 (1979) 203. T. Minami, Y. Ikeda and M. Tanaka, J. Non-Cryst. Solids 52 (1982) 159. M. Tatsumisago, N. Torata, T. Saito and T. Minami, J. Non-Cryst. Sohds 196 (1996) 193. T. Minami, K. Imazawa and M. Tanaka, J. Non-Cryst. Solids 42 ( 1980) 469.
(1996)
491-495
495
[12] T. Minami, J. Non-Cryst. Solids 73 (1985) 273. [I31 J.P. Malugani, and R. Mercier, Solid State Ionics 13 (1984) 293.
[ 141 S. Muto, T. Suemoto, and M. Ishigame, Solid State Ionics 35 (1989) 307. [15] L. Borjesson, ( 1990) 702.
and W.S. Howels,
Solid State Ionics 40/41
[I61 M. Nakayama, M. Hanaya, A. Hatate and M. Oguni, Non-Cryst. Solids 172/ 174 (1994) 1252.
J.