Electrical behaviour of Li 2O–ZnO–SiO 2 glass and glass-ceramics system

Abstract

Sealing quality lithium zinc silicate (LZS) glasses of compositions (wt.%) (a) LZSL– Li 2O: 12.65, ZnO: 1.85, SiO 2: 74.4, Al 2O 3: 3.8, K 2O: 2.95, P 2O 5: 3.15, B 2O 3: 1.2 (low ZnO), and (b) LZSH– Li 2O: 8.9, ZnO: 24.03, SiO 2: 53.7, Na 2O: 5.42, P 2O 5: 2.95, B 2O 3: 5 (high ZnO) were prepared by conventional melt-quench technique and converted to glass-ceramics by controlled crystallization process. The electrical properties of these samples were measured using ac impedance spectroscopy technique over a frequency range of 10 Hz–15 MHz at several temperatures in the range of 323–673 K. The ac conductivity, dc conductivity, dielectric constant and loss factor were obtained from these measurements. The dc conductivity ( σ dc) follows the Arrhenius behaviour with temperature. It is observed that σ dc in LZSL glass is significantly higher than in the LSZH glass and the activation energies for σ dc for LZSL and LZSH glasses are 0.59 and 1.08 eV, respectively. It further observed that the conductivity value decreases nearly one order of magnitude on conversion to glass-ceramics. The behaviour is explained on the basis of distributions and nature of alkali ions and network structures in these samples.