Electrochemical and Economic Analysis of No-Rinse, “True-Cr-Free” Surface Conversion Coatings for a Green, Cost-Saving, Corrosion Protection of 8079 Aluminium Alloy

Increasing the corrosion resistance of aluminium alloys using surface treatments while reducing processes’ environmental impact and saving natural resources has become an urgent need. Some companies that typically use pollutant substances in their process lines have started to test low-environmental-impact products. This paper shows results obtained two commercial products for conversion coating AA8079 rolled-samples: first, rinse, containing CrIII (the so-called “Cr-free” products), second one, no-rinse, utterly free Cr, based on hexafluorotitanate dihydrogen hexafluorozirconate. The bare conversion-coated, organic-coating-covered samples were compared with each other, evaluating when immersed NaCl 3.5 wt.% aqueous solution. experimental showed completely Cr-free no-rinse coatings demonstrate performance comparable “Cr-free”. In addition, a comparison amount water used “rinse” “no-rinse” industrial is reported. Finally, estimation economic balance presented, considering waste reduction be disposed quantity used. aim this was some conversion-coating products, Cr are available nowadays, showing good protective properties low environmental-impact, guaranteeing which not negligible.