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Effect of Nitrogen on Properties of Na2O–CaO–SrO–ZnO–SiO2 Glasses
Authors:Ahmed Bachar  Cyrille Mercier  Arnaud Tricoteaux  Jean‐Christophe Hornez  Anne Leriche  Claudine Follet  Bertrand Revel  Mark R Towler
Affiliation:1. Laboratoire des Matériaux Céramiques et Procédés Associés (LMCPA), Université de Valenciennes et du Hainaut‐Cambrésis, Valenciennes, France;2. Lab. Conditions Extrêmes et Matériaux: Haute Température et Irradiation (CEMHTI), CNRS‐Université d'Orléans, Orléans, France;3. Centre Commun de Mesure RMN, Université Lille1 Sciences et Technologies, Cité Scientifique, Villeneuve d'Ascq, France;4. Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada
Abstract:Glasses in the Na2O–CaO–SrO–ZnO–SiO2 system have previously been investigated for suitability as a reagent in Al‐free glass polyalkenoate cements (GPCs). These materials have many properties that offer potential in orthopedics. However, their applicability has been limited, to date, because of their poor strength. This study was undertaken with the aim of increasing the mechanical properties of a series of these Zn‐based GPC glasses by doping with nitrogen to give overall compositions of: 10Na2O–10CaO–20SrO–20ZnO–(40?3x)SiO2xSi3N4 (x is the no. of moles of Si3N4). The density, glass‐transition temperature, hardness, and elastic modulus of each glass were found to increase fairly linearly with nitrogen content. Indentation fracture resistance also increases with nitrogen content according to a power law relationship. These increases are consistent with the incorporation of N into the glass structure in threefold coordination with silicon resulting in extra cross‐linking of the glass network. This was confirmed using 29Si MAS‐NMR which showed that an increasing number of Q2 units and some Q3 units with extra bridging anions are formed as nitrogen content increases at the expense of Q1 units. A small proportion of Zn ions are found to be in tetrahedral coordination in the base oxide glass and the proportion of these increases with the presence of nitrogen.
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