Treatment of Glass and Steatite Ceramic with Quaternary Ammonium Compounds for the Improvement of Electrical Insulation Resistance

THE adsorption and condensation of water on the surface of insulators was responsible for the failure of much electrical equipment under service conditions in the tropics. From the literature of flotation¹, it was known that the adsorption of a unimolecular film of an amphipathic (polar - non-polar) compound gives to solid surfaces a paraffin-like character, rendering them less readily wetted by water. Some typical flotation reagents were therefore applied to glass and steatite ceramic surfaces in an endeavour to improve their electrical insulation resistances under moist conditions. As might be anticipated from the work of Wark², the quaternary ammonium compounds were effective. The accompanying table shows the results obtained with various substituent radicals for glass microscope slides and steatite terminal bushings. These were cleaned with chromic acid, immersed for about one second in an aqueous solution of the quaternary ammonium salt, and then washed thoroughly in distilled water.