Research on the Impedance Characteristic of Carbon Coils

Micro-coiled carbon fibers were prepared by chemical vapor deposition method(CVD),and aligned via a device designed for executing action with mechanical drawing.Optical microscope was performed to characterize the morphology and aligned state of the fibers.The AC impedance characteristics(impedance |Z| and phase angle θ) of the aligned carbon coils were studied.The results show that impedance and phase angle of the carbon coils keep stable at low frequency,but decrease rapidly with the frequency increasing at high frequency area(f10kHz).Furthermore,the aligned fibers are sensitive to their extending states,and their impedance increases with the extending length prolonging.The study is useful to develop the technique of micro-circuits and micro-sensor based on carbon micro-coils.