Gas desorption properties of tungsten coated graphite materials

Abstract Tungsten-coated graphite materials with a rhenium interlayer (W–Re/G) were developed as plasma facing materials (PFM) of a fusion reactor, by chemical vapor deposition (CVD). Gas desorption properties of various tungsten-coated graphite materials were investigated by using thermal desorption spectroscopy. Major species released from the graphite substrate were H 2 , H 2 O, CO and CO 2 . The desorption of various hydrocarbons such as C x H y ( x =1–4) also was observed at around 500 K. In the W-Re/G sample, the desorption amount of hydrocarbons was an order of magnitude smaller than that of the graphite substrate. In addition, a very large desorption of CO was observed at around 1200 K. For the W–Re/G material, the prebaking temperature required was higher than 1000 K.