Gas-surface interactions of atomic nitrogen with vitreous carbon. (September 2019)

• Record Type: Journal Article
• Authors: Murray, Vanessa J.; Minton, Timothy K.
• Is Part Of: Carbon. Volume 150(2019)
• Page Start: 85
• Page End: 92
• Publication Date: 2019-09
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2019.04.117
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: We have conducted beam-surface scattering experiments with the intent of identifying the reaction mechanisms that are relevant to the ablation of carbon by N atoms at surface temperatures relevant to hypersonic flight. A pulsed molecular beam containing N and N2 with translational energies of 460 and 808 kJ mol -1, respectively, was directed at a vitreous carbon surface held at temperatures in the range 1023–1923 K. Time-of-flight distributions were collected for scattered products with fixed incidence and final angles of θ i = θ f = 45°. Inelastically scattered N and N2 and reactively scattered CN were the only products observed. The scattering dynamics of N and N2 were independent of surface temperature and were indicative of purely impulsive scattering. The scattering dynamics of CN suggested that this reaction product is formed by a mechanism that occurs in thermal equilibrium with the surface – i.e., a Langmuir-Hinshelwood mechanism. The reaction probability to produce CN has an Arrhenius temperature dependence with an activation energy of 207 kJ mol -1 . The relevance of the current results to the hypersonic ablation of carbon in the presence of dissociated air is discussed. Graphical abstract: Image 1086731