Project Experience: Corrosion of Whiskey Cans

The purpose of the analysis was to identify the deposits in selected alcohol bottles and characterize scratches on the inside of aluminum cans. The can samples were cut to expose affected areas. Stereomicroscope was used to show the affected can area vs. the unaffected can area. The affected area showed scratch marks and pit perforation in the can wall. The deposits near the perforation were carbon-based/organic. Imaging also showed numerous scratch marks from a tool or object with tip dimensions of ~ 0.2mm in width (likely related to dragging motion). No visible defects were found in the unaffected can for comparison. The deposits in the alcohol sample were filtered through a filter and analyzed by EMSL. We showed the particulate were carbon-based/organic and also contained aluminum (Al) and phosphorus (P). Small aluminum (Al) fragments were also found. In conclusion, (1) the scratch marks found on the interior can walls were consistent with damage of the organic coating (down to aluminum base), most likely from a drag motion of a tool or object, (2) scratched cans showed pit perforations, and (3) the deposits filtered from alcohol bottles were a mixture of organic matter (with lower amounts of aluminum and occasionally phosphorus) and small aluminum fragments. The ability to use various microscopy instruments proved invaluable regarding corrosion analysis.