Continued Corrosion After Removal of Corrosive Drywall

Copper coupons in sealed glass jars were exposed to corrosive drywall (CDW) and a moisture source while experiencing temperature variation from room temperature to about 120 °F (49 °C). After several weeks of exposure, the CDW source was removed and coupons were replaced into sealed glass jars with a moisture source for extended periods of time under similar temperature cycling. These coupons continued to corrode at a faster rate than coupons that had only been exposed to moisture in the absence of CDW. Analytical scanning electron microscopy (SEM) was used to augment weight change measurements. The results demonstrate that once corrosion is initiated by exposure to CDW, simple removal/replacement of the drywall will not mitigate the corrosion process.