Contents lists available at ScienceDirect Measurement journal homepage: www.elsevier.com/locate/measurement Eect of Bi 2 O 3 addition on the ultrasonic properties of pentaternary borate glasses R. El-Mallawany a , H.A. Afifi b , M. El-Gazery b, , A.A. Ali c a Phys. Dept., Fac. of Sci., Monoua University, Egypt b National Institute of Standards, Ultrasonic Dep. El-Haram, Giza, Egypt c Glass Res. Dept., National Res. Centre, Dokki 12622, Cairo, Egypt ARTICLE INFO Keywords: Ultrasonic velocities Elastic moduli Crosslink density Microhardness and Debye temperature ABSTRACT The eects of addition of Bi 2 O 3 to borate glasses in a series of (75-x) B 2 O 3 -xBi 2 O 3 -10Na 2 O-10CaO-5Al 2 O 3 have been studied through the ultrasonic properties of the glasses. The ultrasonic wave velocities (longitudinal, V L and shear, V S ) were measured at 4 MHz using ultrasonic pulse echo method. Longitudinal L, shear G, bulk K, Yong's E moduli, Poisson's ratio σ, Microhardness (H), softening temperature (T s ) and Debye temperature (θ D ) were measured. Quantitative analysis of the experimental data has been carried based on the bond compression and Makishima-Mackenzie models. 1. Introduction Mechanical properties by using ultrasonic techniques of solid ma- terials have gained considerable interest due to their applications in science and technology. Elastic moduli, Debye temperature, Poissons ratio and microhardness measurements are useful for understanding the coordination changes in materials [15]. Bulk modulus volume rela- tion has been studied to explain the coordination changes in glass network [13]. Debye temperature and Poisson's ratio data give ex- cellent information about cross-link density [4,5]. Borate glasses doped with another glass forming oxide have wide applications in the eld of electronic industry due to their higher conductivity, thermal resistivity and other related properties [6,7]. Structural and coordination changes in bismuth-borate glasses have already been studied and investigated [8]. Optical properties of borate glasses and the eect of addition of CuO, PbO, SrO and Y 2 O 3 have been measured and discussed [912]. Previously, FTIR, UV spectra, optical energy band gap, Urbachs energy and refractive index have been measured on a series of (75-x) B 2 O 3 -xBi 2 O 3 -10Na 2 O-10CaO-5Al 2 O 3 glasses [13]. The present study is to report the eect of addition of Bi 2 O 3 on the ultrasonic wave velocities of (75-x) B 2 O 3 -xBi 2 O 3 -10Na 2 O-10CaO- 5Al 2 O 3 glasses. Also, to calculate the experimental longitudinal L, shear G, bulk K, Yong's E moduli, Poisson's ratio σ, Microhardness H, soft- ening temperature T s and Debye temperature θ D . The experimental results will be interpreted according to Makishima-Mackenzie and bond compressional models. 2. Experimental procedures Borate glass series in the form (75-x)B 2 O 3 -xBi 2 O 3 -10Na 2 O-10CaO- 5Al 2 O 3 (where x = 0, 5, 10,15, 20 and 25 mol.%) were prepared using reagent grade H 3 BO 3 , Na 2 CO 3 , CaCO 3 Al 2 O 3 and Bi 2 O 3 as starting materials as mentioned in the rst part of this study [13] with amor- phous state conrmation. Glass density was determined by using Au- tomatic Gas Pycnometers for true density, Ultrapyc 1200e, and appa- ratus with helium gas and the molar volume V M (cm 3 ) was calculated by using the next equation, = V M/ρ M g (1) where M g is the molecular weight of the glass and ρ is the density of the glass. The ultrasonic velocities measurements were performed at 4 MHz for both shear and longitudinal transducers at room temperature (22 ± 2 °C) using pulse echo technique as explained before [1420]. The time dierence between the rst two echoes (t 1 and t 2 ) was used to calculate the ultrasonic velocities (v L and v S ) using Eq. (2). = v x t t 2 2 1 (2) where x = thickness of the sample. The ultrasoic velocities were re- peated ve times with accuracies V L ± 9 m/s and V S ± 11 m/s. https://doi.org/10.1016/j.measurement.2017.11.028 Received 22 June 2017; Received in revised form 13 October 2017; Accepted 13 November 2017 Corresponding author. E-mail addresses: raoufelmallawany@yahoo.com (R. El-Mallawany), hmafifi@hotmail.com (H.A. Afifi), elgazery@aol.com (M. El-Gazery), ali_nrc@hotmail.com (A.A. Ali). Measurement 116 (2018) 314–317 Available online 14 November 2017 0263-2241/ © 2017 Published by Elsevier Ltd. T