Carbon deposition from acetone during oxidation of iron—the effects of chromium and nickel

Carbon deposition on iron, and its alloys with nickel and chromium, has been produced by catalytic decomposition of acetone in carbon dioxide at 700°C. Nickel has been identified as the major promoter of carbon deposition under these conditions, although iron is also active. When the conditions favoured the occurrence of carbon deposition, the morphology of the magnetite formed was changed from a crystalline structure to a type resembling “breakaway” oxide. Filamentary carbon was formed in all cases, the diameter of the filaments being dependent on whether chromium was present or absent in the substrate material. Initiation of filamentary growth on these materials is discussed.