Preparation of single-helix carbon microcoils by catalytic CVD process

Three-dimensional (3D) single-helix spring-like carbon microcoils (SH-CMCs) were obtained by the catalytic pyrolysis of acetylene at 800–820 °C over the Fe–Ni alloy catalysts; their growth morphologies and microstructure were examined. The diameter of carbon fiber, from which the carbon nanocoils was formed, was about 0.5 μm, the coil diameter was about 1–2 μm, and the coil pitch was about the same with the coil diameter. The SH-CMCs were generally grown by a double-directional growth mode.