Analysis of oxidation behavior under dry air of neat and Ta‐alloyed furan‐resin‐derived carbons heat treated at 3000 °C

Abstract

Oxidation behavior and structural changes of furan-resin-derived carbons heat treated at 3000°C were investigated at 500 and 700°C under dry air. Thermogravimetric analysis (TGA), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were employed to detect and understand this behavior and the changes. Effect of tantalum on antioxidation property of Ta-alloyed carbon was also analyzed. The neat and Ta-alloyed carbons had insignificant weight losses even after being kept at 500°C for 12 h, while the Ta-alloyed carbon had weight loss lower than that of the neat carbon after being kept at 700°C for 6 h. It has been found by XPS that oxidation involves oxygen in internal area as well as on external surface of the carbons. It was also inferred that the carbon stored with oxygen in deeper internal area was easily oxidized. Ta alloying leads to change of the state of the Fermi energy on the specimens, which may cause the antioxidation property.

Analysis of surface oxidation behavior at 500°C under dry air of glass-like carbon heat-treated from 1200 to 3000°C

“…It has been reported that a graphitizable skin is formed on the surface even on the furan-resin-derived carbon bulk above 2500 • C [8]. It has been reported that the carbons alloyed with small amounts of Ta or Ti exhibit oxidation resistance properties [9][10][11][12]. We suggest that Ta-alloying leads to a change in the state of the Fermi energy on the carbons, which may cause the antioxidation property [11].…”

“…It has been reported that the carbons alloyed with small amounts of Ta or Ti exhibit oxidation resistance properties [9][10][11][12]. We suggest that Ta-alloying leads to a change in the state of the Fermi energy on the carbons, which may cause the antioxidation property [11]. However, the oxidation behavior of the * Corresponding author.…”

“…It has been reported that the degree of surface oxidation determines the type of oxygen complexes formed after various oxidative treatments [11,12,[16][17][18][19][20][21][22][23][24]. The O/C ratio for the relative amount of oxygen to carbon is calculated from the areas of the C1s and O1s spectra.…”

“…The O/C ratio for the relative amount of oxygen to carbon is calculated from the areas of the C1s and O1s spectra. Analysis of the relative amount of oxygen to carbon and the kind of surface functional groups is done based on the C1s and O1s spectra [11,[19][20][21][22][23][24]. Additionally, analysis of the oxidized depth is made based on wide-scan spectra [11,24].…”

“…X-ray photoelectron spectroscopy (XPS) is an available technique for characterizing the surfaces of a wide variety of carbon materials [15], including glass-like carbon [11,12,[16][17][18]. It has been reported that the degree of surface oxidation determines the type of oxygen complexes formed after various oxidative treatments [11,12,[16][17][18][19][20][21][22][23][24].…”