The effect of surface pre-treatment on carbon solution and deposition in the iron-methane reaction

摘要: Abstract Two types of deposit, a continuous graphitic film and “nodular” clusters, have been grown on pure iron foils that received different surface pretreatments. It is shown both morphologies occur by solution/precipitation mechanism. A tentative mechanism proposed for the growth nodular clusters based availability isolated metal particles surface. The effect pretreatment conditions rate carbon solution in temperature range 700–900°C reported it maximum achieved, reproducibly, up to 50 μm thickness, after treatment hydrogen 3 hr annealing vacuum (5 × 10−8 Torr) 16 at 990°C. Deposition preceded an induction period which related dissolution, influenced presence oxide dissolved impurities.