Effect of Microstructure on Pulse Electrical Strength of MgO

Abstract

Pulse electrical strengths of hot‐pressed MgO containing 0.3 wt% LiF were measured. Strengths as high as 5.9×10 8 V/in. were obtained on samples 99.8% of theoretical density with 1‐to 3‐μm grain size. An increase of either porosity or grain size resulted in a monotonic decrease in strength. Single‐crystal strengths of 4.0×10 6 V/in. were obtained by polishing samples chemically. A simple recessed‐electrode configuration eliminated corona effects.