Partial substitution of feldspar by alkaline-rich materials in the electrical porcelain insulator for reduction of processing temperature

Abstract

Porcelain is the most widely used overhead power-line insulator. The demands for porcelain insulators have increased dramatically owing to a sharp increase in the electric power demand and supply. Usually, porcelain production demands high sintering temperatures. Herein, an electrical porcelain insulator was produced from Bombowha clay and Arero quartz and partially replaced feldspar with sodium carbonate at a reduced processing temperature. The porcelain samples were prepared by fixing the clay and quartz amount 45 and 10 wt%, respectively, and the portion of feldspar was replaced by 5, 7.5, and 10 wt% of alkaline-rich sodium carbonate. The desired composition was milled, shaped, and finally sintered at 1000, 1100, and 1200 °C. The XRD and SEM results show the early formation of quartz and mullite phases at 1000 °C, which determine the mechanical and dielectric strengths of the porcelains. The dielectric strength of the samples increases with increasing the alkaline-rich sodium carbonate content owing to the vitrification and needle-shaped mullite formation. The porcelain sample with 10 wt% of Na _2 CO _3 content and a sintering temperature of 1200 °C has an optimum dielectric strength of 7.60 kV mm ^−1 .

Keywords

• electrical insulator
• sodium carbonate
• mullite
• quartz
• dielectric strength