Transition between graphene-film and carbon-nanotube growth on Nickel alloys in open-atmosphere flame synthesis

Using open-atmosphere flame synthesis, graphene films and carbon nanotubes (CNTs) are grown directly on nickel and nickel-alloy substrates. The gas-flow input CH4 to H2 ratio (1:10) is held constant. For nickel, copper–nickel, and Inconel, few-layer graphene (FLG) grows at 850 °C. Transitional growth from FLG to CNTs is observed on nickel, copper–nickel, and Inconel, as the substrate temperature is decreased to 500 °C. CNT growth is found for nitinol at 500 °C; however, graphene growth is not observed for nitinol at elevated temperatures for the examined experimental conditions.