Influence of TiB2 addition upon thermal stability and decomposition temperature of the MgH2 hydride of a Mg-based mechanical alloy

Intensive mechanical milling was used to synthesize a MgH2 (50 wt.%) + TiB2 (50 wt.%) composite. Thermal stability of the composite versus H-desorption was studied employing the thermodesorption spectroscopy (TDS) method. The TDS data have revealed that TiB2 addition decreases the dissociation temperature of the MgH2 hydride by about 50 deg C. An X-ray photoelectron spectroscopy analysis has shown that TiB2 addition does not alter the surface chemical state of particles of the MgH2 hydride, a component of the composite under consideration. The effect of decreasing decomposition temperature of MgH2 due to addition of TiB2 has been attributed to catalytic influence of a TiB2 particle surface on processes of associative hydrogen desorption taking place on the surface of MgH2 particles, as well as to a higher degree of dispersion of magnesium dihydride provided by the presence of TiB2.