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Glass formation, properties and structure of glasses in the P2O5WO3K2OAl2O3 system
Journal of Non-Crystalline Solids 80 (1986) 527-532 North-Holland, Amsterdam
527
GLASS FORMATION, PROPERTIES A N D S T R U C T U R E OF GLASSES IN THE PzOs-WO3-KzO-AI203 SYSTEM QI Yafan and HE Li Institute of Optics & Electronics, Academia Sinica, Chengdu, PRC
Glass formation in the P20~-WO3-K20-A1203 system was investigated and the glassforming regions are presented. The properties of the glasses in the P20~-WO3-K20-AI203 system (AI203 8 tool.%) are reported. The colouration of glass was studied. It was found that W ~+ ions make glass blue. Infrared spectra were measured by means of making KBr pills. Results of the investigation suggest that P-O-P, P-O-W, and W - O - W bonds form a continuous network in the phosphate glasses. So we suggest that tungsten trioxide is a glass former.
1. Introduction Because of the characteristics of tungsten-phosphate glasses, such as the semiconductor, electrohromic [1] and coiouration properties, some scientists are interested in them. It seems to be necessary to study the role of tungsten trioxide in glass formation and the structural condition of the tungsten trioxide. This paper reports the results of an investigation of the glass formation, properties, and structures in the P 2 0 5 - W O 3 - K 2 0 - A I 2 0 3 system.
2. Experiments and results 2.1. Raw materials Starting materials were reagent-grade P205, W O 3 , K 2 C O 3 and AI(OH)3. 2.2. Glass formation The experimental method of ref. [2] was used. Fig. 1 shows the glassforming region of the P2Os-WO3-K20-AI203 system when the A1203 content is 0, 5, 8 mol.%. 0022-3093/86/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
528
Qi Yafan, He Li
I
Properties of glasses in the P20~-WO3-K20-AI203 system
~o~
~07/~ 20
5fS/•35
zA
5
gO5
s2/ ~ Xs~ 32A _ _ _ y \72 /
Fig. 1. Glass formation in the P2Os-WO3-KzOA1203 system: I, 0 mol.% A1203; II, 5 mol.% Al2Os; III, 8 mol.% A1203.
. . . . 72 52 .~2 /.2
2.3. Glass properties Glass compositions within the above mentioned region (A1203 8 mol.%) were selected and were then melted in a 300 ml crucible to obtain 500 g batches. Figs. 2-5 show properties of the glasses. Table 1 gives the electronic properties.
2.4. Colouration of glasses A solution containing W 5+ was prepared by means of a method in which W 6+ was reduced to W 5+ by zinc in a HCI solution, and .the transmission of the solution was measured. T h e results are shown in figs. 6 and 7. Table 2 gives the compositions of the glasses for the P2Os-WO3-K20-A1203 system.
d. 5.8 3.6 I2O.
3,4 3.2 3,/IO
d
2'o
<,,%,. "
. . . . . .
Jo
4b
jo
3
IOO.
wo, moi z
Fig. 2. Density against composition. (1) 10K20
-,,,,,
8A1203 XWO3(82-X)P205 ,
(2)
15K20 8A1203XWO3(77- X)P2Os, 20K20 8A1203XWO3(72-X)P205.
(3)
,.........
BO60
Fig. 3. Coefficient of thermal expansion against composition.
Qi Ya[an, He Li I Properties of glasses in the PzOs-WO~-KzO-AI,O~ system
529
Tg °C
/
580 560
620
540
600
.520
Z
"
o
580
500
~
/
56o g.
480 460
I
1o
540
I
20
I
I
I
3o
40
50
520
I
J
,
,
I
10
20
5o
40
50
WO 5 tool%
W03 rnol%
Fig. 4. Transformation temperature against composition.
Fig. 5. Softening temperature against composition.
Table 1 Glass electronic properties of the PzOs-WOa-K20-AI203 system No.
Thickness (cm)
Area (cm 2)
Total electronic resistance (~O)
Resistivity (,Q cm)
PWKA-1 2 3 4 9 14 18
0.20 0.20 0.20 0.20 0.2(t 0.20 0.20
3.1416 3.1416 3.1416 3.1416 3.1416 3.1416 3.1416
1.8 x 11112 1.5 x lip a 5.7x 1012 4.1xl012 4.0x 1012 2.9x 1012 2.2 x l012
2.9 x 1013 2.4 x 1013 9.1x1013 6.6x I(P 3 6.4 x 1013 4.6x 10 ]3 3.5 X 1013
Table 2 The composition of the glasses in the P20~-WO3-K20-AI203 system PWKA-
Composition (mol.%)
No.
Composition (tool.%)
riO.
1 2 3
P20~
WO3
K20
AI203
62 57 52
20 25 3(1
10 10 10
8 8 8
No.
14 18
4 9
P~O~
WO3
K20
47 47
35 3(I
10 15
Composition (tool.%) P20~
WO~
K20
AI:O~
47 47
25 20
20 25
8 8
Al20s
530
Oi Yafan, He Li / Properties of glasses in the P2Os-WO~-K20-AI203 system
"u
"Z;
lO0
loo
,,
80
x'~
~....Z._ x
6O
6O
40
4O
20
.0
/¢
/
0
I
~40
pldKA- ~8
80 x~
i
i
I
.580 4.20 460
I
~
i
•
500 540 580 620
y]m
340
~80
420
,
,
460
,
,
500 540 580
~nl
Fig. 6. Transmission of solution containing W 5+.
Fig. 7. Transmission of glass of the PzOsWO3-K20-A1203 system.
We compared fig. 6 to fig. 7 and consider that the blue of the glasses is due to the W 5+.
2.5. Infrared spectra T h e glass infrared spectra were measured by means of the K B r pill method. Fig. 8 shows the results. ,
pw~
1,oo
ldoo
66o
zbo
Fig. 8. IR spectra of glasses of the P205 WO3-K20-AI203 system.
,
620
Qi Yafan, He Li / Properties of glasses in the P205-WOj-K20-AI20~ system
531
3. Discussion
3.1. Glass formation and structure It can be seen from fig. 1 that glasses can be formed when P205 contains between 10-20 and 5 0 - 6 0 m o 1 . % WO3 in the a b o v e mentioned system. Although the structure is very seriously broken, stable glass can still be formed when the glass former contains 10-20 mol.% WO3. C o m p a r i n g fig. 1 to Jing's result [3], we found both of them to be identical; here WO3 is Nf' which is a glass former. T h e I R spectra verify that WO3 gest into the network. We can see the positions of the peaks are at 1250, 900-980, 750 and 500 cm -1. When WO3 is added into phosphate glass, some of the P - O - P bonds are broken. T h e (WOa) substitutes for (PO4) and P - O - P , P - O - W and W - O - W bonds form a continuous structural network. Peaks at 1250, 900-980, 750 and 500 cm -t are attributed to the vibration of Vas O P O [4,5], Vas P O W [4], Vs P O P [5] and Vs W O W [4] (and OPO). With an increase of the WO3 content, the peak at 1250 cm -~ is strengthened, the p e a k at 750 cm -t is reduced; these results verify that the vibrations of Vas O P O and Vs P O P are reduced. T h e variations are attributed to depolymerization of the (PO4) structural network due to the added WO3 in the network. Existence of a peak at 9 0 0 - 9 8 0 c m -L and the Vs W O W vibration are due to the (WO4) substitution for (PO4), and P - O - W and W - O - W bonds are formed. Reduction of the peak at 900 cm -~ and strengthening of the peak at 980 cm -1 reflect the reduction of the vibration Vas P O W with a decrease of the WO3 content and an increase of the K 2 0 content. We consider that WO3 is a glass former. This result coincides with the conclusions of Gelsing [6] and Mirochnichenko [4].
3.2. Glass colouration in the P2Os-WO3-K20-AI203 system It is known from our results that the glasses are blue. C o m p a r i n g the transmission of the solution containing W 5+ to the transmission of the glasses, it can be seen that the maxima of both are at 4 2 0 - 4 3 0 nm, but the positions of the absorption peaks of both are at 600 nm. It is known from the free energy of the oxide [7] that the stability of tungsten oxides are in the order WO3"W2Os"WO2-W203 to b e c o m e unstabilized. In addition to W 6+, the W 5+ ion is very stable. Lagzdons [8] confirmed the existence of W 5+ in tungsten phosphate glasses containing barium. Hence, we consider that W 5+ ions m a k e the glasses blue. T h e blue of the glasses b e c a m e dark with an increase of acid and WO3 content in the system.
532
Qi Ya[an, He Li / Propertiesof glasses in the PzOs-WO3-K20-AI203 system
4. Conclusion
The glass formation, properties, and structure were studied and discussed. (1) The glasses can be formed when containing WO3 between 10-20 and 50-60 mol.% in the P2Os-WO3-K20-A1203 system. (2) Density, transformation temperature and softening temperature increase, but the coefficient of thermal expansion and transmission decrease with an increase of the WO3 content. (3) W 5÷ ions make the glasses blue, and the glasses become dark with an increase of acid and an increase of the WO3 content in the system. (4) (WO4) gets into the network of the glasses; continuous chains of P-O-P, P - O - W and W - O - W bonds are formed so that we consider WO3 to be a glass-former.
References [1] [2] [3] [4] [5] [6] [7]
S.K. Deb and K.F. Shaw, USP, Nos. 3, 521,941 (July, 1970) 28. Oi Yafan and Dai Yisheng, J. Chinese Silicate Soc. 11 (1983) 266. Jing Zhonghong, J. Chinese Silicate Soc. 9 (1981) 326. O. Ya. Microchnichenko and V.V. Mombelli, Soviet J. Glass Phys. Chem. 5 (1979) 25. Gan Fuxi, Chen Shizheng and Huang Guosong, Acta Optica Sinica 2 (1982) 252. R.J.H. Gelsing, Phys. Chem. Glasses 7 (1966) 185. C.W. Keenan, J.H. Wood and D.C. Kleinfelter, General College Chemistry (in Chinese) (1981) p. 32. [8] Yu. L. Lagzdons, Ya.Ya Kleperis and A.R. Lusis, J. Glass Phys. Chem. (in Russian) 5 (1979) 141.
527
GLASS FORMATION, PROPERTIES A N D S T R U C T U R E OF GLASSES IN THE PzOs-WO3-KzO-AI203 SYSTEM QI Yafan and HE Li Institute of Optics & Electronics, Academia Sinica, Chengdu, PRC
Glass formation in the P20~-WO3-K20-A1203 system was investigated and the glassforming regions are presented. The properties of the glasses in the P20~-WO3-K20-AI203 system (AI203 8 tool.%) are reported. The colouration of glass was studied. It was found that W ~+ ions make glass blue. Infrared spectra were measured by means of making KBr pills. Results of the investigation suggest that P-O-P, P-O-W, and W - O - W bonds form a continuous network in the phosphate glasses. So we suggest that tungsten trioxide is a glass former.
1. Introduction Because of the characteristics of tungsten-phosphate glasses, such as the semiconductor, electrohromic [1] and coiouration properties, some scientists are interested in them. It seems to be necessary to study the role of tungsten trioxide in glass formation and the structural condition of the tungsten trioxide. This paper reports the results of an investigation of the glass formation, properties, and structures in the P 2 0 5 - W O 3 - K 2 0 - A I 2 0 3 system.
2. Experiments and results 2.1. Raw materials Starting materials were reagent-grade P205, W O 3 , K 2 C O 3 and AI(OH)3. 2.2. Glass formation The experimental method of ref. [2] was used. Fig. 1 shows the glassforming region of the P2Os-WO3-K20-AI203 system when the A1203 content is 0, 5, 8 mol.%. 0022-3093/86/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
528
Qi Yafan, He Li
I
Properties of glasses in the P20~-WO3-K20-AI203 system
~o~
~07/~ 20
5fS/•35
zA
5
gO5
s2/ ~ Xs~ 32A _ _ _ y \72 /
Fig. 1. Glass formation in the P2Os-WO3-KzOA1203 system: I, 0 mol.% A1203; II, 5 mol.% Al2Os; III, 8 mol.% A1203.
. . . . 72 52 .~2 /.2
2.3. Glass properties Glass compositions within the above mentioned region (A1203 8 mol.%) were selected and were then melted in a 300 ml crucible to obtain 500 g batches. Figs. 2-5 show properties of the glasses. Table 1 gives the electronic properties.
2.4. Colouration of glasses A solution containing W 5+ was prepared by means of a method in which W 6+ was reduced to W 5+ by zinc in a HCI solution, and .the transmission of the solution was measured. T h e results are shown in figs. 6 and 7. Table 2 gives the compositions of the glasses for the P2Os-WO3-K20-A1203 system.
d. 5.8 3.6 I2O.
3,4 3.2 3,/IO
d
2'o
<,,%,. "
. . . . . .
Jo
4b
jo
3
IOO.
wo, moi z
Fig. 2. Density against composition. (1) 10K20
-,,,,,
8A1203 XWO3(82-X)P205 ,
(2)
15K20 8A1203XWO3(77- X)P2Os, 20K20 8A1203XWO3(72-X)P205.
(3)
,.........
BO60
Fig. 3. Coefficient of thermal expansion against composition.
Qi Ya[an, He Li I Properties of glasses in the PzOs-WO~-KzO-AI,O~ system
529
Tg °C
/
580 560
620
540
600
.520
Z
"
o
580
500
~
/
56o g.
480 460
I
1o
540
I
20
I
I
I
3o
40
50
520
I
J
,
,
I
10
20
5o
40
50
WO 5 tool%
W03 rnol%
Fig. 4. Transformation temperature against composition.
Fig. 5. Softening temperature against composition.
Table 1 Glass electronic properties of the PzOs-WOa-K20-AI203 system No.
Thickness (cm)
Area (cm 2)
Total electronic resistance (~O)
Resistivity (,Q cm)
PWKA-1 2 3 4 9 14 18
0.20 0.20 0.20 0.20 0.2(t 0.20 0.20
3.1416 3.1416 3.1416 3.1416 3.1416 3.1416 3.1416
1.8 x 11112 1.5 x lip a 5.7x 1012 4.1xl012 4.0x 1012 2.9x 1012 2.2 x l012
2.9 x 1013 2.4 x 1013 9.1x1013 6.6x I(P 3 6.4 x 1013 4.6x 10 ]3 3.5 X 1013
Table 2 The composition of the glasses in the P20~-WO3-K20-AI203 system PWKA-
Composition (mol.%)
No.
Composition (tool.%)
riO.
1 2 3
P20~
WO3
K20
AI203
62 57 52
20 25 3(1
10 10 10
8 8 8
No.
14 18
4 9
P~O~
WO3
K20
47 47
35 3(I
10 15
Composition (tool.%) P20~
WO~
K20
AI:O~
47 47
25 20
20 25
8 8
Al20s
530
Oi Yafan, He Li / Properties of glasses in the P2Os-WO~-K20-AI203 system
"u
"Z;
lO0
loo
,,
80
x'~
~....Z._ x
6O
6O
40
4O
20
.0
/¢
/
0
I
~40
pldKA- ~8
80 x~
i
i
I
.580 4.20 460
I
~
i
•
500 540 580 620
y]m
340
~80
420
,
,
460
,
,
500 540 580
~nl
Fig. 6. Transmission of solution containing W 5+.
Fig. 7. Transmission of glass of the PzOsWO3-K20-A1203 system.
We compared fig. 6 to fig. 7 and consider that the blue of the glasses is due to the W 5+.
2.5. Infrared spectra T h e glass infrared spectra were measured by means of the K B r pill method. Fig. 8 shows the results. ,
pw~
1,oo
ldoo
66o
zbo
Fig. 8. IR spectra of glasses of the P205 WO3-K20-AI203 system.
,
620
Qi Yafan, He Li / Properties of glasses in the P205-WOj-K20-AI20~ system
531
3. Discussion
3.1. Glass formation and structure It can be seen from fig. 1 that glasses can be formed when P205 contains between 10-20 and 5 0 - 6 0 m o 1 . % WO3 in the a b o v e mentioned system. Although the structure is very seriously broken, stable glass can still be formed when the glass former contains 10-20 mol.% WO3. C o m p a r i n g fig. 1 to Jing's result [3], we found both of them to be identical; here WO3 is Nf' which is a glass former. T h e I R spectra verify that WO3 gest into the network. We can see the positions of the peaks are at 1250, 900-980, 750 and 500 cm -1. When WO3 is added into phosphate glass, some of the P - O - P bonds are broken. T h e (WOa) substitutes for (PO4) and P - O - P , P - O - W and W - O - W bonds form a continuous structural network. Peaks at 1250, 900-980, 750 and 500 cm -t are attributed to the vibration of Vas O P O [4,5], Vas P O W [4], Vs P O P [5] and Vs W O W [4] (and OPO). With an increase of the WO3 content, the peak at 1250 cm -~ is strengthened, the p e a k at 750 cm -t is reduced; these results verify that the vibrations of Vas O P O and Vs P O P are reduced. T h e variations are attributed to depolymerization of the (PO4) structural network due to the added WO3 in the network. Existence of a peak at 9 0 0 - 9 8 0 c m -L and the Vs W O W vibration are due to the (WO4) substitution for (PO4), and P - O - W and W - O - W bonds are formed. Reduction of the peak at 900 cm -~ and strengthening of the peak at 980 cm -1 reflect the reduction of the vibration Vas P O W with a decrease of the WO3 content and an increase of the K 2 0 content. We consider that WO3 is a glass former. This result coincides with the conclusions of Gelsing [6] and Mirochnichenko [4].
3.2. Glass colouration in the P2Os-WO3-K20-AI203 system It is known from our results that the glasses are blue. C o m p a r i n g the transmission of the solution containing W 5+ to the transmission of the glasses, it can be seen that the maxima of both are at 4 2 0 - 4 3 0 nm, but the positions of the absorption peaks of both are at 600 nm. It is known from the free energy of the oxide [7] that the stability of tungsten oxides are in the order WO3"W2Os"WO2-W203 to b e c o m e unstabilized. In addition to W 6+, the W 5+ ion is very stable. Lagzdons [8] confirmed the existence of W 5+ in tungsten phosphate glasses containing barium. Hence, we consider that W 5+ ions m a k e the glasses blue. T h e blue of the glasses b e c a m e dark with an increase of acid and WO3 content in the system.
532
Qi Ya[an, He Li / Propertiesof glasses in the PzOs-WO3-K20-AI203 system
4. Conclusion
The glass formation, properties, and structure were studied and discussed. (1) The glasses can be formed when containing WO3 between 10-20 and 50-60 mol.% in the P2Os-WO3-K20-A1203 system. (2) Density, transformation temperature and softening temperature increase, but the coefficient of thermal expansion and transmission decrease with an increase of the WO3 content. (3) W 5÷ ions make the glasses blue, and the glasses become dark with an increase of acid and an increase of the WO3 content in the system. (4) (WO4) gets into the network of the glasses; continuous chains of P-O-P, P - O - W and W - O - W bonds are formed so that we consider WO3 to be a glass-former.
References [1] [2] [3] [4] [5] [6] [7]
S.K. Deb and K.F. Shaw, USP, Nos. 3, 521,941 (July, 1970) 28. Oi Yafan and Dai Yisheng, J. Chinese Silicate Soc. 11 (1983) 266. Jing Zhonghong, J. Chinese Silicate Soc. 9 (1981) 326. O. Ya. Microchnichenko and V.V. Mombelli, Soviet J. Glass Phys. Chem. 5 (1979) 25. Gan Fuxi, Chen Shizheng and Huang Guosong, Acta Optica Sinica 2 (1982) 252. R.J.H. Gelsing, Phys. Chem. Glasses 7 (1966) 185. C.W. Keenan, J.H. Wood and D.C. Kleinfelter, General College Chemistry (in Chinese) (1981) p. 32. [8] Yu. L. Lagzdons, Ya.Ya Kleperis and A.R. Lusis, J. Glass Phys. Chem. (in Russian) 5 (1979) 141.