Corrosion of Wires on Wooden Wire-Bound Packaging Crates

Abstract Wire-bound packaging crates are used by the US Army to transport materials. Because these crates may be exposed to harsh environments, they are dip-treated with a wood preservative (biocide treatment). For many years, zinc-naphthenate was the most commonly used preservative for these packaging crates and few corrosion problems with the wires were observed. Recently, copper based alternatives to zinc naphthenate have been used, and corrosion problems have been observed. Here, we present the results of laboratory corrosion testing of 10 different wood treatments to see which preservatives have the potential to cause corrosion problems. The laboratory test was designed to mimic the production process; wires from packaging crates were attached to wood and dipped in the wood preservative and stored in a polyethylene bag for either 2 or 8 weeks to simulate how the crates are stored in the warehouse. The amount of corrosion was examined both visually and gravimetrically. Zinc naphthenate and Preservative A were the least corrosive preservatives, and there were no statistical differences between these two preservatives. The remaining treatments had at least 5 times more corrosion than these two preservatives. Three of the 10 treatments showed a linear increase in the amount of corrosion with time, suggesting that they were still corroding as rapidly at week 8 as they were at week 2 and present a high risk of corrosion. From these results, Preservative A (a copper ethanolamine complex containing citric acid) appears to be the least corrosive alternative to zinc naphthenate.