The Rusting of Iron

Abstract

THE experiments made by Mr. J. Newton Friend, and described by him in NATURE of September 27, confirm similar experiments previously made by me, and furnish further evidence that the rusting of iron is primarily a result of acid attack. That cast iron, a very complex material frequently containing a high percentage of sulphur and phosphorus, decomposes hydrogen peroxide “with astonishing rapidity,” and that the metal becomes covered with rust in a few minutes, is not, however, to be referred to catalytic action, as Mr. Friend suggests, but is a consequence of the formation of acids by the oxidation of some of the impurities present in the iron, and of the subsequent electrolytic action. As Mr. Friend says, “the purer the iron the less is the action of the peroxide upon it,” which is another way of stating that the intensity of action will be determined by the amount of acid formed on the surface of each particular sample of metal when in contact with the peroxide.