PRETREATMENT PROCESS FOR ALUMINUM AND HIGH ETCH CLEANER USED THEREIN

摘要

A high etch cleaner for aluminum and aluminum alloy substrates that leads to enhanced corrosion protective performance of a variety of anti-corrosion pretreatments. The cleaner comprises low levels of silicate of from 0 to 250 ppm, 50 to 500 ppm of at least one chelator, and has a pH of from 11.0 to 13.5. The cleaner may be used to etch from 0.5 to 4.0 grams per meter squared from substrates. Substrates treated with the cleaner and then coated with a variety of anti-corrosion pretreatments and outer coatings show enhanced corrosion resistance compared to substrates cleaned with standard cleaners that have low etch rates, high silicate levels and no chelating agents followed by anti-corrosion pretreatments and outer coatings.