Effect of Alumina Reinforcement on the Physical and Electrical Properties of Kaolin-Glass Ceramic Insulators

Abstract

This work provides a comprehensive investigation into the influence of alumina (Al₂O₃) reinforcement on kaolin–glass ceramic composites, focusing on their physical and electrical properties. A series of samples with fixed kaolin–glass ratios (50:50) and varying alumina contents (0–20 wt%) were sintered at 900, 1000, and 1100 °C. The results revealed that the addition of alumina significantly enhanced densification and dielectric behavior, with 15% alumina at 1000 °C producing the optimal performance. At these conditions, the dielectric constant reached 21.38 at 0.1 MHz, water absorption dropped to 1.97%, and bulk density increased to 2.1559 g/cm³. These enhancements were attributed to microstructural densification and interfacial polarization mechanisms. The findings demonstrate that kaolin–glass–alumina composites have strong potential for application as high-voltage insulators in demanding environments, particularly under humid conditions.