Preparation of Low Temperature Pyrolytic Carbon from cis-1, 2- Dichloroethylene by Resistance Tube Furnace Method

Abstract

Low temperature deposition of pyrolytic carbon onto an artifical graphite plate (8 cm in length) from cis-1, 2-dichloroethylene was attempted by the use of a resistance tube furnace placed horizontally. Source material was supplied with argon gas through an inlet nozzle placed at 0.5 cm upstream from the end of a substrate plate. The deposition began at 500° C and proceeded rapidly with the rise of temperature until 700° C. Most of the experiments were carried out 600° C because the nozzle was plugged up with deposited carbon in the experiments above 700° C. The optical microstructures of the pyrolytic carbon were arranged in the order of columnar, dense isotropic, and porous isotropic types along the gas stream. The length of the columnar zone was extended from 1 cm to 8 cm with the increase of a gas flow rate from 35 m//min to 190 m/Jmin. Deposition rates calculated from thicknesses were not uniformly extended over the whole surface of the plate, but had a maximum in the isotropic zone. The position at which the maximum rate was observed was shifted to the downstream with the increase of a gas flow rate. The increase of concentrations of dichloroethylene from 7 vol% to 25 vol% affected the deposition rate more, but the length of the columnar zone and the positions of maximum deposition rate less. The maximum deposition rate was about 150, um/hr and the pyrolytic carbon layer obtained showed a great adhesion to the graphite substrate. The characteristics of the pyrolytic carbon prepared at 600° C were as follows: specific grayity; 1.50, specific resistance; 3.7 x 10-2 ohmm, X-ray parameter ei; 3.88 A, Le; 10 A, content of Cl; 4.3 atomic%.