Electrically insulative alumina and silica-based coatings up to 500 mum in thickness have been deposited on steel substrates using a sol-gel composite technology. Coatings are produced by spray depositing a ceramic paint consisting of fine ceramic powders dispersed in a sol-gel solution to form a coating. Coatings are then dried at 343 K and fired at 723 K to pyrolyze the organic components. A room temperature dielectric strength up to 5000 V-AC has been achieved at coating thicknesses as low as 300 mum on a steel substrate. Coatings have been fabricated that pass a 'hi-pot' test of 1275 V-AC for 1 s at operating temperatures as high as 673 K. These results have been achieved through control of coating microstructure and the elimination of surface porosity. This technology provides cost effective electrical insulation for a wide range of applications including low profile integrated heating elements based on inexpensive steel and aluminum substrate materials.