Stimulating Effect of Graphite Admixture on Hydrogen Sorption−Desorption Properties of Mechanically Activated Titanium Powder

Abstract

The effect of graphite admixture on hydrogen sorption-desorption properties of mechanically activated electron microscopy, temperature-programmed reaction, and temperature-programmed desorption techniques. The major effect of graphite addition was found to be the formation of microporous carbon matrix particles containing randomly distributed titanium particles only several nanometers in diameter. This powder architecture enhances hydrogen transport to the titanium surface without hindrances and promotes titanium-hydrogen interaction by modifying the titanium surface and subsurface layers with interstitial carbon atoms.

Effect of N, C and B interstitial atoms on local bonding structure in mechanically activated TiH2/h-BN, TiH2/C, and TiH2/B mixtures

“…The TiH2 desorption was tested by temperatureprogrammed desorption (TPD) under flow conditions. Details of these experimental methods are published elsewhere [3][4][5]. Table 1 shows phase compositions of the respective samples after milling, after TPD, as well as H 2 evolution under milling, and H 2 desorption and peak temperatures recorded under TPD.…”

“…High-energy ball milling is used to accelerate the process after significantly decreasing the powder size [1][2][3]. The decomposition efficiency can be improved, when compounds, which prevent particle sticking (graphite, h-BN), are added to the reactive powder before milling [3][4][5]. As a result, the H 2 evolution temperature drastically falls.…”

Effect of Hydrogen on the Mechanical Properties of Stainless Steels

“…at sufficiently high temperatures. The kinetics of hydrogen uptake from the gas phase depends upon the elements present at the surface, [13][14][15][16][17] and especially on the composition of the gas. [1] Gas components with a higher affinity to iron than that of hydrogen, e. g. O 2 , CO, SO 2 , H 2 O vapour, inhibit hydrogen adsorption by blocking potential adsorption sites.…”

Boron Enhanced Synthesis of Ti-hydride Nanoparticles by Milling Ti/B in Hydrogen Flow

“…A basically inert matrix protects fresh Ti-hydride nanofragments from atmospheric impact but assures hydrogen access to the fresh surface of Ti nanofragments. Ball-milling of Ti and graphite in H 2 is a highly effective technique to synthesize nanocrystalline Ti-hydride powder [3,6,12,13]. However, the formation of a TiC surface layer can block the Ti surface and suppress the Ti-H 2 interaction [12,13].…”

“…Ball-milling of Ti and graphite in H 2 is a highly effective technique to synthesize nanocrystalline Ti-hydride powder [3,6,12,13]. However, the formation of a TiC surface layer can block the Ti surface and suppress the Ti-H 2 interaction [12,13]. The application of other materials, in particular boron, to promote the mechanochemical synthesis of metal hydrides is poorly studied.…”