Comparative analysis of graphite oxidation behaviour based on microstructure

摘要: Abstract Two unidentified powdered graphite samples, from a natural and synthetic origin respectively, were examined. These materials are intended for use in nuclear applications, but have an unknown treatment history since they considered proprietary. In order to establish baseline comparison, the samples compared two commercial flake with varying impurity levels. The characterized by conventional techniques such as powder X-ray diffraction, Raman spectroscopy fluorescence. results indicated that all four very similar, low levels good crystallinity, yet exhibit remarkably different oxidation behaviours. oxidized microstructures of examined using high-resolution scanning electron microscopy at acceleration voltages. relative influence each factor affecting was established, enabling structured comparison oxidative Based on this analysis, it possible account measured differences reactivity. material lowest reactivity which having highly visible crystalline perfection, large particles high aspect ratio no traces catalytic activity. second sample, had identical inherent microstructure, found increased due presence small impurities. This also exhibited more gradual reduction rate higher conversion, caused accumulation impede oxidation. sample highest be milled, material, despite its evident crystallinity. attributable smaller particle size, impurities extensive damage structure jet milling. Despite displaying intermediate reactivity, comparable contaminated sample. absence needle coke-derived behaviour. work illustrates single most important when comparing origins is assessment microstructure. approach has added benefit identifying further potential processing steps limitations customization.