High-voltage insulators are the biggest and most complex products produced from silicate ceramic materials. They are critical components in transmission and distribution of electric energy. The reliable behavior of insulators over decades, in all locations, and in all climatic zones of earth, is the most crucial demand put on them.

However, aging and strength-decrease caused by microcracks in the insulator microstructure are problematic, because microcracks grow under operational conditions and when stressed by temperature changes. To decrease microcrack formation during porcelain insulator aging, we must maximize reduction and resolution of undesired residual quartz particles inserted into the porcelain microstructure by kaolin and feldspar. A novel solution to this problem is the use of bauxite instead of alumina.