Experimental study on the oxidation behavior and microstructural evolution of NG-CT-10 and NG-CT-20 nuclear graphite

摘要: NG-CT-10 and NG-CT-20 are newly developed grades of nuclear-grade graphite from China. In this study, their oxidation behaviors were experimentally investigated using thermal gravimetric analysis. Microstructural evolution before after was scanning electron microscope, mercury intrusion, Raman spectroscopy. The apparent activation energy nuclear is 161.4 kJ/mol in a reaction temperature range 550–700 °C that 153.5 kJ/mol 550–650 °C. the inner diffusion control regime approximately half kinetics regime. At high temperatures, binder phase preferentially oxidized over filler particles small pores generated binder. No new large or deep on surfaces. Oxygen can diffuse along boundaries through phase, but cannot into spaces between nanocrystallites particles. Filler starting at outer surfaces, sizes do not decrease following oxidation.