Ultrasonic velocity in sodium borate glasses

Abstract

Ultrasonic velocities in sodium borate glasses are measured as a function of composition at a frequency of 10 MHz and at a temperature of 298 K by making use of the ultrasonic pulse echo overlap method. Elastic properties of these glasses are analysed in terms of the elastic internal energy due to deformation; elastic resistances of the network-former, B203, and the modifier, Na20, are obtained as a function of composition from the plot of MV 2 against x 2, where M is the molar mass of sodium borate glasses, Vthe velocity of sound and x2 the mole fraction of NazO. The elastic resistances of B203 and Na20 are as follows: (i) for x2<0.33, the elastic resistance of B203 is smaller than that of N a20; (ii) at x2=0.33, the elastic resistances of B203 and Na20 are equal; (iii) for x2>0.33, the elastic resistance of B203 iS greater than that of Na20; (iv) at x2,,~0.15, the elastic resistances of B203 and Na20 become respectively maximal and minimal; (v) at x2,,~0.23, the elastic resistances of B203 and Na20 become respectively minimal and maximal; (vi) above x 2 = 0.36, the elastic resistance of Na20 becomes negative.

Elastic properties and spectroscopic studies of fast ion conducting Li2OZnOB2O3 glass system

“…Hence, elastic properties are suitable for describing the glass structure as a function of composition [13]. There have been studies and reports [14][15][16] on several binary alkali borate glasses, which show that there is a correlation between elastic properties and borate glass structure. In Na 2 O-B 2 O 3 glass system [17], the elastic properties have been discussed in terms of boron coordination.…”

Structural Analysis of Some Alkali Diborate Glasses

“…Previously [21] it has been argued that the high value of the ratio K bc /K e more than 3 indicates that network bond bending (or non-network bond compression) processes predominate when these materials are subjected to bulk compression. The rigidity of the stoichiometry sodium diborate glass network is maximized according to some former studies [5,26]. Thus, analysis of the computed elastic moduli according to the bond-compression model may be achieved of these glass series [18][19][20] as follows.…”

“…These two fundamental units can be arbitrarily combined to form either the so-called super-structure or different B x O y structural groups like boroxol ring, pentaborate, tetraborate, diborate groups etc. In the alkali borate glass systems, each alkali oxide is associated with a proportional quantity of B 2 O 3 ; so that, the number of the structural units depends on both the nature and the total concentration of the added modifiers, and can often give rise to tightly organized structures resulting in intermediate order [1][2][3][4][5]. In sodium borate glasses there are three types of structural groupings; namely boroxol rings, tetraborate units and diborate units.…”

“…As a result, one Na 2 O forms two BO 4 units, which makes the network structure three-dimensional [6][7][8][9]. Kodama [5] analyzed the elastic properties of sodium borate glasses in terms of three structural units defined as B 3 − is a non-bridging oxygen. It is assumed that these structural units have their respective elastic constants defined on the basis of a thermodynamic * corresponding author; e-mail: mohamed_s_gaafar@hotmail.com equation of deformed body, so the rigidity of the glass will increase with the structural unit c and decreases with the structural unit b.…”

Effect of Doping by Different Transition Metals on the Acoustical Properties of Alkali Borate Glasses

“…Hence, elastic properties are suitable for describing the glass structure as a function of composition [1]. There have been studies and reports [2][3][4] on several binary alkali borate glasses, which show that there is a correlation between elastic properties and borate glass structure. In Li 2 O-B 2 O 3 glass system [4], the elastic properties have been discussed in terms of boron coordination.…”