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CHARACTERIZATION AND VIBRATIONAL
SPECTRA OF THE VITREOUS DOMAIN EXISTING IN THE TERNARY DIAGRAM Li2O-CdO-P2O5
B. Elouadi, M. Ouchetto, Ch. Garrigou-Lagrange
To cite this version:
B. Elouadi, M. Ouchetto, Ch. Garrigou-Lagrange. CHARACTERIZATION AND VIBRATIONAL SPECTRA OF THE VITREOUS DOMAIN EXISTING IN THE TERNARY DIAGRAM Li2O-CdO- P2O5. Journal de Physique Colloques, 1982, 43 (C9), pp.C9-359-C9-362. �10.1051/jphyscol:1982969�.
�jpa-00222498�
JOURNAL DE PHYSIQUE
Colloque C9, supplement au n°12, Tome 43, decembre 1982 page C9-359
CHARACTERIZATION AND VIBRATIONAL SPECTRA OF THE VITREOUS DOMAIN EXISTING IN THE TERNARY DIAGRAM L i20 - C d O - P205
B. E l o u a d i , M. O u c h e t t o and Ch. G a r r i g o u - L a g r a n g e
Laboratoire de Chimie du Soli.de Appliquee, Departement de Chimie, Faculte des Scienoes, Avenue Ibn Batota, Rabat, Morocco and Centre de Recherches Paul Pascal, Domaine Uni-versitaive, 33405 Talence, Prance
Résumé.- L'analyse radiocristallographique a été réalisée sur des phosphates mixtes de Li et de Cd trempés à partir de l'état liquide. Cette technique a permis de délimiter un large domaine vitreux existant au sein du diagramme ternaire Li20-Cd0-P205. La stabilité thermique des verres ainsi isolés a été précisée après un recuit effectué pendant 14 heures sur plusieurs échantillons vitreux à différentes températures variant de 80 à 550°C. La spectroscopie Raman a été utilisée afin d'examiner l'évolution de la structure du verre au sein de son domaine d'existence.
Abstracts.-Xray analysis carried out on supercooled melts of mixed Li and Cd phosphates has permitted the determination of the border of a wide glass forming region inside the ternary system Li20-Cd0-P20g. The heat stability of the isolated glasses has been determined using the annealing technique for 14 hours at different temperatures between 80 and 550°C for many compositions. Raman scattering was used to examine the evolution of glass structure inside the vitreous domain .
1. Introduction.- Despite the well known ability of P-Og and the alkali and alkaline earth phosphates to vitrify on rapid cooling from the liquid state, these materials have received very limited attention compared with silicate and borate glasses (1-5^ . This is probably due to their limited commercial application (5| .Nevertheless
important research work has been carried out to study the structure and physical properties of these glasses (1-5).
The present study was carried out in order to determine the glass forming region included in the ternary diagram Li20-Cd0-P20g. It is also concerned by the evolution of the vitreous structure with the stoichiometry inside this domain.
2. Glass forming region.- Li2C0,s CdCOg and (NH4)2HP04 of reagent grade (Merck pa) were used as starting materials for the preparation of the desired glass composition.
Mixtures of these chemicals are ground in an agate mortar and preheated at 300°C before being melted at 1000°C in a gold crucible. The quenching may be achieved
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1982969
JOURNAL DE PHYSIQUE
Lip 0
Fig. 1
.-
Glass forming r e g i o n a t 1000°C i n t h e t e r n a r y system Li20-Cd0-P205.e i t h e r i n a i r o r i c e around t h e glass f r o n t i e r .
The weight o f t h e m e l t may vary from 2 t o 159 o f mixed oxides. Xray d i f f r a c t i o n was performed on each sample prepared i n o r d e r t o v e r i f y t h e q u a l i t y o f i t s s t a t e : glass o r c r y s t a l l i n e . It has p e r m i t t e d t h e d e l i m i t a t i o n o f t h e v i t r e o u s domain i n s i d e the t e r n a r y system Li20-Cd0-P205. F i g . 1 shows the glass forming r e g i o n obtained a t 1OOO0C.
A l l t h e v i t r e o u s samples obtained were t r a n s p a r e n t s t i f f m a t e r i a l s . The compounds i s o l a t e d o u t s i d e t h e glass domain are covered by a t h i n p o l y c r y s t a l l i n e f i l m
,
as t h e composition i s becoming simultaneously more and more t r a n s l u c e n t .Annealing o f glass compositions f o r 14 hours a t v a r i o u s temperatures has p e r m i t - t e d the d e t e r m i n a t i o n o f a t r a n s i t i o n temperature (Tv+,) from t h e v i t r e o u s t o the c r y s t a l l i n e s t a t e . The change from t h e former t o t h e l a t t e r s t a t e has been confirmed by X-ray a n a l y s i s . Table I gives t h e e v o l u t i o n o f Tv,c along the l i n e (0.5-x)Li20, xCdO, 0.5 P205. The i n t r o d u c t i o n o f cd2' i n t o t h e v i t r e o u s network seems t o increase t h e value o f Tv
,,
and then t h e thermal s t a b i l i t y o f these phosphate glasses.3. Raman s c a t t e r i n g study.- Raman s c a t t e r i n g and I R spectroscopy have been w i d e l y used t o c h a r a c t e r i z e t h e phosphate glass s t r u c t u r e s (1, 4-10). The Raman spectra recorded here were explained on t h e basis o f t h e f o l l o w i n g v i b r a t i o n s :
VsPOP 700cm-~ ; u PO z1040cm-~ ; vsP02 = l l 7 0 c m - I ; vaP02 = 1240-1280~111' 1 -1s 3
and vP = 0.1320cm
.
.
ir Table I
.
E v o l u t i o n o f TV+, along the l i n e (0.5-x)Li 20, xCdO, 0.5 P205 CompositionTv + c
x = 0.25
(395 _f 5)"C
x = 0.5
(490 -
+
10)"C1 I
x = 0.0
(180
t
10)"Cx = 0.1
(290 -
+
10)"CF i g . 2
.-
E v o l u t i o n o f t h e Raman spectrum w i t h P205 p r o p o r t i o n i n t h e phosphate g l a s s e s : [ ( I- x) -
x l LiZO, x CdO, xPZO5.-
V i t r e o u s P205 c o n s i s t s o f a 3-dimensional s k e l e t o n o f (PO4) t e t r a h e d r a s h a r i n g t h r e e o f t h e i r f o u r c o r n e r s . The non bonding oxygen i s d o u b l y bonded t o t h e phosphor atom. T h i s d o u b l e bond g i v e s r i s e on t h e Raman spectrum t o a band a t 1350cm-I, due t o t h e v P
=
0 v i b r a t i o n . The l i n k between two a d j a c e n t t e t r a h e d r a i n s u r e d by t h e bonds POP i s d e t e c t e d by t h e v i b r a t i o n vsPOP s i t u a t e d a t 700cm- 1.
As p r o g r e s s i v e l y t h e i n t e r t e t r a h e d r a l bonds a r e destroyed, t h e g l a s s s t r u c t u r e tends t o be c o n s t i t u t e d by l o n g c h a i n s o f (PO4) t e t r a h e d r a . T h i s i s supported by t h e f a c t t h a t i n t r o d u c t i o n o f a m o d i f i e r o x i d e (LipO, CdO o r b o t h ) i n t o PZO5gives r i s e t o t h e p r o g r e s s i v e d i s a p p e a r i n g o f v P =0, c h a r a c t e r i s t i c o f t h e 3-dimensional g l a s s s t r u c t u r e .
F i g . 2 shows some Raman s p e c t r a o b t a i n e d f o r v a r i o u s c o m p o s i t i o n s o f t h e g l a s s
C9-362 JOURNAL DE PHYSIQUE
forming r e g i o n . I t i s c l e a r from t h i s f i g u r e t h a t glass samples c o n t a i n i n g t h e same mole f r a c t i o n o f P205 g i v e r i s e t o analogous Raman spectra. The s u b s t i t u t i o n o f l i t h i u m oxide by cadmium oxide seems t o have a very l i m i t e d e f f e c t on t h e glass s t r u c t u r e , according t o t h e Raman study.
References :
1.- Mac KENZIE J. 0.
,
Modern aspects o f t h e v i t r e o u s s t a t e v o l . 1-3, London Butterworths 1960-1964.2.- SCHOLZE H., Le verre, Nature, S t r u c t u r e e t Proprietes, I n s t i t u t du verre, P a r i s 1980 and references included.
3
.-
Verres e t R e f r a c t a i r e s , N04/5, J u i 11 et-Octobre 1971.4.- RAWSON H., I n o r g a n i c glass-forming systems, London Academic Press 1967.
5.- BARTHOLOMEW R. F., J.Non-Cryst. S o l i d s
-
7 (1972) 221.6.- BUES W. and GEHRKE H. W., 2 . Anorg. A l l g . Chem.
-
288, (1956) 291.7.- BUES W. and GEHRKE H. W., Z. Anorg. A l l g . Chem.
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288, (1956) 307.8.- CORBRIOGE 0. E. C. and LOWE E.
J.,
J. Chem. Soc. (1954) 493.9.- ROUSE J r . G. B., MILLER P. J. and RISEN J r . W. M.
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Non-Cryst. S o l i d s28
(1978) 193.
10.- C. GARRIGOU-LAGRANGE, M. OUCHETTO and 8. ELOUADI Proc. 8th i n t e r . Conf. on Raman Spectroscopy Bordeaux 1982.
