Corrosivity of Pressurized Liquids in Aerosol Cans

The complex corrosion mechanisms for pressurized aqueous solutions in contact with various aerosol containers were studied electrochemically. A pressurized corrosion cell consisting of an aerosol container serving as the working electrode, a platinum rod serving as a hybrid reference-counter electrode, and the pressurized liquids as the electrolyte was designed and fabricated. The correlation of the results between two accelerated electrochemical corrosion tests, namely the galvanostatic polarization test and a 24-hour accelerated constant polarization potential test, and a 10-week storage test, was excellent. It was found that the addition of 0.1% disodium phosphate (DSP) to the aqueous solutions pressurized with a 10% isobutane-propane propellent blend changed the color of the systems to colorless, produced an electrodeposition of colloidal particles, and shifted the site of the crevice corrosion from the bulk-stagnant interface towards the stagnant area. Three distinct and characteristic zones of the polarization potential responses were observed during the anodic galvanostatic polarization measurements, and their mechanisms are discussed.