Electrical Conductivity of Na2O–B2O3–SiO2–Cr2O3 Glass System

Abstract

The electrical properties of glasses composed of 8Na₂O–(22 – x)B₂O₃–70SiO₂–xCr₂O₃, where x varies from 0.3 to 6 mol %, heat-treated at 550°C for 48 h, are studied. The structure of the glasses is studied using scanning electron microscopy and X-ray powder diffraction (XRPD). It is established that in all glasses of the selected compositions, during heat treatment, an interconnected phase-separated structure is formed and the eskolaite phase (α-Cr₂O₃) also crystallizes. When comparing the obtained values of electrical resistance and activation energy of electrical conductivity of chromium-containing glasses and glass without Cr₂O₃ composed of 8Na₂O⋅22B₂O₃⋅70SiO₂ and iron-containing glasses of similar compositions, it is suggested that the studied glasses with Cr₂O₃ possess ionic conductivity and the values of the specific volume resistance of chromium-containing and iron-containing glasses do not differ from each other. The introduction of Cr₂O₃ in sodium borosilicate glasses does not affect their electrical conductivity.