Ultrasonic investigations of some bismuth borate glasses doped with Al2O3

Abstract

The velocities of longitudinal and transverse ultrasonic waves in different compositions of 5Al 2 O 3 -29Na 2 O-(66−x)B 2 O 3 −xBi 2 O 3 glass system were measured at 4 MHz at room temperature using the pulse-echo technique. The velocity data were used to determine the elastic moduli and the dimensionality of the studied glasses. The observed changes in the elastic moduli of the glasses were related to the modifier role of Bi 2 O 3 content. The results revealed that the density increased with increasing Bi 2 O 3 content, which was attributed to the increase in the compactness and packing of the glass network. The ultrasonic data were analysed in terms of creation of new bonds of Bi 2 O 3 attached to the structural units of the borate network. The new bonds decreased the average crosslink density and the number of network bonds per unit volume along with a weakening of the different modes of vibrations, which in its turn decreased the ultrasonic velocity. Quantitative analysis was carried out using Makishima-Mackenzie model in order to obtain more information about the rigidity of these glasses.

Ultrasonic and Thermal properties of Bismuth borotellurite glasses doped with NdCl3

“…Longitudinal elastic (L), shear elastic moduli (G), bulk elastic moduli (K), Young's elastic moduli (E) and posission's (σ) are calculated using the longitudinal ultrasonic velocity, the shear ultrasonic velocity and the density as shown in the next relations [20,26]. Value of these moduli listed in Table 2 and shown in Fig.…”

“…Poission's ratio is known as the ratio between the lateral to longitudinal strain produced when tensile forces are applied [25,26]. It depends on dimensionality and cross link density.…”

“…The cross link density c is calculated from the relation (11) (12) where n c is the number of cross-links per cation (number of bridging bond per cation minus two) in the oxide I, N c is the number of cation per glass formula and ηis the total number of cations per glass formula unit. In the system under study the total number of cations per glass formula is decreeing consequently the cross link density is decreasing therefore the Poission's ratio increases from 0.25 with 0% NdCl3 to 0.27 with 2% NdCl3 [25], the decrease of Poission's ratio to 0.26 with higher concentrations of NdCl3 (5 % and 10%) may be attributed to other predominant factors such as the increase of tensile strain or dimensionality [26].…”

Metrological and Optical –Mechanical Study of a Band Pass Glass Filter Working as Photometric Filter

“…where V L and V s are the longitudinal and transverse sound velocities and ρ is the density of glass samples. The sound velocities also allow the determination of Young's modulus (E), the bulk modulus (K), the micro-hardness (H) and Poisson's ratio (σ) is defined for any structure as the ratio between lateral and longitudinal strain produced when tensile force is applied, using the following equations [11][12][13]:…”

Study of bagasse and cassava rhizome effects on the physical, mechanical and structural properties of soda-lime borate glasses

“…Among the diverse methods required high precision, ultrasonic non-destructive technique is found to be the versatile tool for understanding the association of the structural characteristics and mechanical properties of amorphous materials [20]. The ultrasonic examination helps to understand the interatomic and ionic forces including the potentials in lattice structure [21,22]. The acoustic velocity as well as the density of glasses can be considered as parameters of elastic constants related directly to changes in the glass structure.…”