Chemical durability and thermal in salt free aqueous solutions of sodium molybdophosphate glasses
L. Bih1*, L. Abbas1, H. Bih2, M. Amalhay3, H. Mossadik3, A. Nadiri4, A.Yacoubi4
1Equipe Sciences des Matériaux, Faculté des Sciences et Techniques Errachidia, B.P 509, Boutalamine, Errachidia, Maroc
2LCME, Département de chimie, FST-Guéliz, Marrakech, Maroc
3CERPHOS, Casablanca, Maroc
4Département de chimie, Faculté des Sciences de Meknes, Maroc
* Corresponding author. E-mail: email@example.com
Received: 26 June 2008; revised version accepted: 02 August 2008
Thermal and chemical durability studies of the phosphate glasses belonging to the binary MoO3-P2O5 and the ternary Na2O-MoO3-P2O5 systems are reported. The chemical resistant attack tests carried out on the free alkaline MoO3-P2O5 glasses show that the glass associated with the P/Mo ratio 2 has the high chemical durability. It shows also a high glass transition temperature value. The above findings are interpreted in terms of the cross-link density of the glasses and the strength of the M–O bonds (M = P, Mo). The influence of Na2O addition on the properties of this binary high- water resistant glass is studied. It is found that the chemical durability along with the other physical properties are reduced by the incorporation of Na2O in the glass matrix. The results were explained by assuming the formation of non-bridging oxygens and weak bonds. The mechanism of the dissolution of these glasses is proposed.
Keywords: phosphate; molybdenum; glasses; density; glass transition temperature; chemical durability.