Thermal, mechanical and electrical properties of lithium phosphate glasses doped with copper oxide

Abstract

Lithium phosphate glasses with the basic composition (${\hbox {P}}_{2} {\hbox {O}}_{5}$ 50 and ${\hbox {Li}}_{2} \hbox {O}$ 50 mol%) series by the addition of copper oxide (0, 10, 15 and 20 g/100 g) were prepared by a melt quenching technique. Fourier-transform infrared (FTIR) absorption spectra and X-ray diffraction (XRD) analysis were used to characterize the glass samples. Thermal expansion and mass density were also measured. The different mechanical properties of the prepared glasses were measured by an ultrasonic non-destructive technique. Additionally, both frequency and temperature dependence of alternating-current conductivity were measured in the frequency range of 40 Hz–1 MHz and the temperature range of 308–488 K. Moreover, direct current conductivity was also measured for the same temperature range. FTIR measurements confirm the appearance of the bands of phosphate groups and the assumption of bonds formed between Cu and P. XRD spectra approve the amorphous nature of the studied glasses. Thermal expansion and mass density of the prepared samples show an increase in values by increasing the CuO content. The mechanical properties of the studied glasses (hardness ($H_{\mathrm{v}}$), Young’s modulus (E), elastic modulus (L), bulk modulus (K), shear modulus (G) and Poisson’s ratio ($\nu$)) were positively affected by the CuO content, reflecting a better packed structure. Furthermore, the electrical conductivity values of the prepared glasses are identified to increase with an increase in both temperature and CuO content. Such trends agree with the data obtained by thermal expansion and FTIR. The progressive addition of CuO is assumed to improve thermal, mechanical and electrical properties of the prepared lithium phosphate glasses.