Deposition of columnar and laminar forms of carbon on polycrystalline nickel foils

✍ Scribed by Thomas Baird

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 931 KB
• Volume: 15
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(77)90326-8

✦ Synopsis

distinct forms of carbon in terms of morphology and crystallinity have been produced on polycrystallin$ Ni foils by pyrolysis of propene (50Torr). A thick layer (up to 10 pm) of columnar carbon (d (woz, = 3.40 A; I?. = 33 Kcabmole) was-obtained within the temperature region 320-380°C. From 380-800°C a thin layer of lammar graphrte (dtm2, = 3.36 A; E. = 16 kcabmole) was formed. As a consequence of the temperature gradient along the length of the foils in these experiments both forms of carbon could be produced simultaneously. Bulk diffusion and surface diffusion mechanisms have been proposed to account for the growth of the columnar and laminar products respectively. At -700°C migration of Ni metal particles to the cooler foil edges occurred and resulted in the formation of non-graphitic filaments. Preliminary studies with butadiene have revealed similar deposition characteristics and activation energies to those of propene.