Carbides of Group 4 and 5 Metals as Functional Materials for Hydrogen Energy

The hydrogen permeation through the carbides of group 5 metals was investigated at 573 - 773 K by examining the hydrogen absorption by sheet type specimens of group 5 metals with carbides layers. The thickness of carbide layers ranged 100 nm to several μm. Rapid hydrogen absorption was observed if Pd coating was prepared on the specimen surfaces over the carbide layers, although the absorption rate without Pd coating was significantly smaller. These observations indicated that the carbides of group 5 metals have rather high permeability for hydrogen, although their surfaces are sensitive to poisoning effects by impurities in hydrogen gas such as water vapor.