Synthesis of carbon microcoils and nanocoils on various substrates

This research investigates the role of the substrate in the synthesis of carbon coils. Coils were produced on tungsten, titanium, and glassy carbon substrates via chemical vapor deposition (CVD) of acetylene (C₂H₂) on electrochemically deposited nickel at 800°C, but the growth varied among the samples. Coils were also produced on pure nickel by the same CVD method. Using tungsten as a substrate, carbon coils intermixed with thin carbon nanotubes were produced in high-yield from nickel particle clusters. On the titanium substrate, carbon coils were synthesized in small, high-yield patches with few co-produced carbon nanotubes. Synthesis from nickel clusters on glassy carbon usually resulted in amorphous carbon, but sparse, low-yield coil growth was observed. Carbon coils were also synthesized when pure nickel wire was used without a separate substrate. These results indicate the nickel catalyst controls the production of carbon coils, but the substrate has some effect on the yield. Carbon coils synthesized were either microcoils, which have diameters of a few microns, or nanocoils, which have diameters of one or two hundred nanometers.