THERMAL OXIDATION KINETICS OF MULTILAYER CARBON NANOTUBES IN AN OXYGEN STREAM

  
V.Petrova,
  
Т.M.Terentieva
 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Omeliana Pritsaka str.,3, Kyiv, 03142, Ukraine
Powder Metallurgy - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2019, #03/04
http://www.materials.kiev.ua/article/2812

Abstract

For the first time, oxidation reactions of multilayer carbon nanotubes in isothermal conditions have been studied. With a steady increase in temperature from 923 to 1173 K, the time dependence of the oxidation of multilayer carbon nanotubes varies from the owing line to the S-shaped curve with saturation. The oxidation rate of the samples at the sites of linear growth at 923 K is Vox = 4.38 ∙ 10–7 mol/sec. Starting from 973 K for 360 sec, internal overheating of the sample activates fast reactions of carbon oxidation. In the range 1023–1173 K, the total rates increase exponentially Vox = 1.19 ∙ 10–6–1.97 ∙ 10–5 mol/sec. According to the Arrhenius equation, the kinetic parameters of carbon thermal oxidation are calculated. The activation energies of the oxidation reactions of multilayer carbon nanotubes in the range 973–1173 K were found at Ea ≈ 169 ± 9 kJ/mol. The frequency characteristics of factor A0 were defined as ≈(1.0–3.1) ∙ 106 sec–1. The activation parameters of the oxidation reactions of multilayer carbon nanotubes are close to the theoretical activation energy of graphite oxidation (172 kJ/mol).


KINETIC PARAMETERS, MULTILAYER CARBON NANOTUBES, OXIDATION, POWDER, REACTION