Removal of Ormosil Films from Metal Substrates

Abstract

A process for chemical removal of organically-modified silicate (Ormosil) coatings from aluminum alloy substrates without degradation of the underlying metal. An Ormosil film is treated with a zincate solution. The zincate solution dissolves the Ormosil film and deposits a thin, easily-removed layer of zinc onto the aluminum alloy surface, which prevents base-activated dissolution of the underlying metal. The zinc layer may be removed using dilute phosphoric acid, leaving the surface of the aluminum alloy intact. Consequently, the sol-gel coating may be removed while the integrity of the aluminum alloy substrate is maintained.