Table 1.
Carbon-14 production mechanisms and cross sections, [5].
Table 2.
Relative reaction rates between different oxidising gases and graphite at 0.1 atm and 800°C [16].
Table 3.
Temperatures of the three different regimes of graphite oxidation sourced from different studies.
Fig 1.
Virgin PGA machined for analysis; (1) 12mm x 7mm discs, (2) 4mm x 2mm discs and (3) 4mm x 4mm x 4mm cubes.
Fig 2.
Experimental methods for different gas mixtures.
Fig 3.
Oxidation rates of virgin PGA graphite during the nitrogen control experiment (experiment 3).
Error bars are from calculated standard error of the mean.
Fig 4.
Oxidation rates of cuboidal virgin PGA graphite samples in air, black squares, and in air following heating in nitrogen, red circles.
Error bars are from calculated standard error of the mean.
Fig 5.
Oxidation rates of small disc virgin PGA graphite samples in air, black squares, and in air following heating in nitrogen, red circles.
Error bars are from calculated standard error of the mean.
Fig 6.
Electron micrographs from PGA graphite oxidised in air at different temperatures along with virgin material for comparison.
Fig 7.
Electron micrographs from PGA graphite oxidised in air following flushing with nitrogen at different temperatures along with virgin material for comparison.
Fig 8.
Avizo reconstruction from XRT of PGA graphite prior and post oxidation at 650°C.
Fig 9.
Avizo reconstruction from XRT of PGA graphite prior and post oxidation at 900°C.
Fig 10.
X-ray tomograms from PGA graphite pre and post oxidation at 650°C in air.
Fig 11.
X-ray tomograms from PGA graphite pre and post oxidation at 900°C in air.