yes, my buddies did mention that they had to hose down the parts with fresh water to keep the metal from corroding. alluminum does corrode (exfoliation), but it takes forever to start. It was my buddy who helped bring the black boxes home. He said that they found them several days prior to the news report, but were not allowed to bring them up until told to do it.
From what was shown on news footage, the parts were blasted with firehoses as they came out of the water and prior to loading on the decks. Many sites have also pointed this out. Don't the ship firehoses use surface water?