City gas is thermally decomposed at above 1300℃. 
We synthesized CMCs using city gas by Hot-filament CVD method. 
Conclusion
SEM images of CMC using various gas
(a) Acetylene gas、 (b)City gas
CMCs have large coil gap and indicate good elasticproperty.
MaterialsDecompositiontemperature (℃)
Reaction
temperature(℃)
City gas1３00
Acetylene770770
(mg/cm2)
(a)(b)
Hot-Filament CVD method
Methane(88%)
Ethane(6%)
Propane(4%)
Buthane(2%)
Component of ｃity gas
Synthesis conditions and Results
Morphology of CMC using city gas
As grown CMCHeat treated CMC at 2500℃ for 4h
0.3360.3370.3380.3390.340.3410.3420.3430.344
100012001400160018002000
Raman Shift [cm-1]
0.3360.3370.3380.3390.340.3410.3420.3430.344
100012001400160018002000
Raman Shift [cm-1]
D-band
G-band
Raman Spectrum
As grown CMCHeat treated CMCat 2500℃ for 4h
TEM Observation
We successed to synthesize CMCs using City gas as raw materials.
CMCs are composed of amorphous carbon and were graphitized after heat-treated at 2500℃ for 4h underAr atmosphere.
Vapor phase preparation of carbon microcoils(CMCs) using city gas
○M. Nanami, M. Hasegawa, S. Yang, X. Chen and S. MotojimaDepartment of Applied Chemistry, Faculty of Engineering, Gifu University, Gifu 501-1193, Japan
E-mail: motojima@apchem.gifu-u.ac.jp
Carbon microcoils (CMCs) are prepared by chemical vapor deposition (CVD) method using Ni as a catalyst and have an interesting 3D-helical/spiral structure with a coil diameter of micrometer orders. Since CMCs have various special characteristics such as electromagnetic wave absorption and electrical characteristic, CMC have been used in cosmetics or tactile sensors. But CMCsare expensive and it is difficult to be applied in diverse fields.  So, in this work, we attempted to use city gas as raw materials that cost a tenth of acetylene gas used as before.
Optimum temperature for CMC growth is 770℃.
Tungsten filament
Passan electric current 
Stainless bar
City gas、H2、 H2S
Quartz board
Graphite substrate
Exhaust