Effects of h-BN particles on the structure, oxidation behaviour, and kinetics of C/C composites fabricated via CVI. (January 2021)

• Record Type: Journal Article
• Authors: Niu, Zi-bo; Xiao, Peng; Li, Zhuan; Zhang, Bengu; Li, Jin-wei; Liu, Zeyan; Li, Yang
• Is Part Of: Corrosion science. Volume 178(2021)
• Publication Date: 2021-01
• Subjects: C/C composite -- Hexagonal boron nitride -- Deposition structure -- Oxidation kinetics; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2020.109059
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: Effect of h-BN on deposition mechanism, morphology and pore system was studied. Effect of internal stress on crack formation and interface debonding was studied. Change of oxidation-controlling mechanisms by these structural factors was studied. Self-healing effect of B2 O3 causes the change of rate-limiting step at 800−900 °C. Abstract: Effects of h-BN content on deposition mechanism, morphology, and pore system of C/C composites, which led to different oxidation behaviours and kinetics, were investigated. Oxidation of the C/C composites is controlled by mixed diffusion/reaction mode in entire temperature range (600−900 °C). Owing to different pore systems and spherical morphologies with fewer cracks and well-bonded interface, C/CBN composites have higher diffusion resistance, causing much lower oxidation rates and higher activation energy at 600−800 °C. Moreover, due to self-healing effect of B2 O3, at 800−900 °C oxidation of the C/CBN composites is controlled by diffusion rather than the mixed mode.