Oxidation kinetics of diamond, graphite, and chemical vapor deposited diamond films by thermal gravimetry

Abstract

Oxidation kinetics of diamond films synthesized by plasma-assisted chemical vapor deposition (CVD) in flowing oxygen were evaluated using thermal gravimetric analysis. The oxidation rates of diamond films, measured in the 500 to 750 °C range, were significantly lower than natural diamond, which was lower than grafoil and pyrolytic forms of graphite. The mechanisms of oxidation in the CVD diamond films and natural diamond were explored by scanning electron microscopy and Auger electron spectroscopic examination of localized regions. In CVD films, oxidation occurred preferentially at grain boundaries, local defects, and diamond-like carbon containing regions during the early stages of oxidation process. The results suggest that preferred orientation of diamond crystallites in the CVD film plays a major role on its oxidation behavior.

Experimental and kinetic modeling of oxygen-enriched air combustion of municipal solid waste

“…The function f(a) is dependent on the assumed reaction mechanism. Various forms of this function have been published (Kok and Okandan, 1996;Rao and Bardon, 1995;Zhang et al, 1997;Gopalakrishan et al, 1994;Allen and Paul, 1995;Joshi et al, 1990). However, it is often used in the form analogous to the solid waste reactions kinetics:…”

Diameter dependence of oxidative stability in multiwalled carbon nanotubes: Role of defects and effect of vacuum annealing

“…It has been demonstrated that high temperature air oxidative occurs preferably at kink sites. 13 In addition to defects, the oxidative stability of CNTs can also be influenced by nanotube diameter 14 and local curvature of CNTs. 14 Bond curvature has been found to affect the oxidation of single wall CNTs.…”

Oxidation electronics: bond–band–barrier correlation and its applications

“…They found that the forward scattering of the infrared from the diamond windows changes from 0.8% before heating to 6.2% after heating at 1070 K for 255 seconds while the transmittance drops by 6-12% after heating. Nimmagadda et al [509] suggested that oxidation occurs preferentially at regions of grain boundaries, local defects and diamond-like carbon phase during the earlier stages of oxidation. An investigation by Zhu et al [510] revealed that diamond oxidation occurs at $ 1070 K and suggested that diamond oxidation depends on the crystal orientation and defect density.…”