CORROSION RESISTANCE PROPERTIES OF SUB-MICRON TO MICRON-SIZED TiO_2 PARTICLE-DOPED ORMOSIL COATINGS ON ALUMINUM ALLOYS

摘要

Organically-modified silicate (Ormosil) films have been found to provide good corrosion resistance for 2024-T3, 6061-T3, and 7075-T6 aluminum alloy substrates. Significant enhancement in corrosion resistance properties of these films were observed upon addition of sub-micron to micron-sized TiO_2 particles to the Ormosil coating as determined using accelerated salt spray and electrochemical analysis. R_(corr) values derived from potentiodynamic polarization curves were found in the range (147-258) k OMEGA cm~2 for doped and non-doped Ormosil thin films. E_(pit) values for doped Ormosil coatings showed the dramatic change into the positive potential region from (-214 to + 100) mV for the non-doped Ormosil to (+403 to + 1899) mV for particle-doped Ormosil thin films.