question: Corrosion is usually defined as the degradation of metals due to what?
distractor3: oscillatory process
distractor1: crystalline process
distractor2: nuclear process
correct_answer: electrochemical process
support: Corrosion is usually defined as the degradation of metals due to an electrochemical process. The formation of rust on iron, tarnish on silver, and the blue-green patina that develops on copper are all examples of corrosion. The total cost of corrosion in the United States is significant, with estimates in excess of half a trillion dollars a year.