Electrical properties of Na2O-CaO-P2O5 glasses doped with SiO2 and Si3N4

• Published in: Solid state ionics 2018-11, Vol.325, p.157-162
• Main Authors: Wójcik, N.A., Jonson, B., Barczyński, R.J., Kupracz, P., Möncke, D., Ali, S.
• Format: Article
• Language: English
• Subjects: Impedance spectroscopy; Oxynitride glass; Sodium-calcium-phosphate glasses
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2018.08.011

Sodium-calcium-phosphate glasses doped with SiO2 or Si3N4 having similar sodium ion concentrations were prepared by melt quenching. The conductivity was measured by impedance spectroscopy under nitrogen atmosphere in a wide frequency range (10 mHz–1 MHz) and wide temperature range (153–473 K). At 36.6 °C, DC conductivities of all glasses vary between 1.1 ∗ 10−12 and 8.9 ∗ 10−12 S cm−1 and have similar activation energies (between 0.87 and 0.91 eV), which are characteristic for an ionic conduction mechanism. The analysis of AC conductivities showed that the spectra are governed by one dynamic process – hopping of the mobile charge carriers - which may be described i.e., by the ‘concept of mismatch and relaxation’ or by the ‘random barrier’ model. The obtained results confirmed a higher influence of nitrogen incorporation on the various glass conductivity parameters than shown for silicon doping alone. However, the influence of fundamental structural changes on the glass conductivity is less relevant as is the overall sodium ion concentration, which remains the decisive factor for a high ion conduction. •Electrical properties of Na-Ca-P-O glass system doped with SiO2 or Si3N4 are studied.•The entire AC conductivity spectra are governed by one dynamic process – Na+ hopping.•The negative mixed modifier effect in phospho-silicate glasses seems to be small.•The influence of nitrogen incorporation on glass conductivity is higher than that of silicon.•The impact of structural variations on the conductivity is not as prevalent as the Na+ content.