Characterisation of pyrolytic graphite exposed to molten LiCl–KCl salt

Abstract

Graphite based materials are proposed as one of the candidate materials for metallic fuel reprocessing involving high temperature molten chloride salt environment. Pyrolytic graphite (PyG) was deposited on graphite substrates by thermal chemical vapour deposition using methane gas to enhance their performance in molten chloride environments. The structural features of the PyG deposit were characterised using X-ray diffraction by measuring interlayer spacing, crystallite size and preferred orientation. The present study discusses the corrosion behaviour of PyG in molten LiCl–KCl eutectic salt at 873 K. The PyG samples tested in molten salt for 2000 h in controlled argon atmosphere exhibited negligible weight loss. The as deposited and corrosion tested samples characterised using optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy showed no significant change in surface morphology. The study showed excellent corrosion resistance of PyG in molten salt under inert atmosphere.