The electric strengths of glasses with different sodium contents

✍ Scribed by J. Vermeer

• Book ID: 104162593
• Publisher: Elsevier Science
• Year: 1956
• Weight: 311 KB
• Volume: 22
• Category: Article
• ISSN: 0031-8914
• DOI: 10.1016/s0031-8914(56)90216-6

✦ Synopsis

A comparison is given of the electric strengths of four kinds of glass with different sodium contents, measured at temperatures between --183°C and +200°C, using approximately linearly rising voltages of durations between 30 sec and 10 -5 sec. The reproducibility of the measurements was within 2{%.

The values of the intrinsic electric strength ranged from 9 MV/cm to 11.5 MV/cm. No correlation with the ionic conductivities was found in accordance with the electronic nature of the intrinsic breakdown, which is generally accepted. No effect of specimen thickness, temperature, voltage rise time or electrode material was found.

On the other hand if the temperature was high enough and the voltage duration long enough to permit motion of ions a breakdown strength was found decreasing with specimen thickness, temperature and voltage duration. Thin silver electrodes gave lower values than liquid electrodes. In this region the glass with the highest sodium content showed the smallest breakdown strength and conversely. This means a support for the supposition that here ions play a dominating part.