Hydrogen effect on the morphology and structure of 3D porous titanium in the HFCVD-diamond growth environment

Titanium hydride was obtained from hydrogenation process on pure titanium (Ti) using a hot filament chemical vapor deposition reactor. The Ti samples were produced from powder metallurgy technique and present three-dimensional porosity. The experimental parameters of the hydrogenation process were controlled in a similar way as those for diamond growth. The pressure inside the reactor was kept at 6.6 kPa for a H2 flow rate of 100 sccm and hydrogenation time of 1 hour. The distance from the filaments to the Ti surface was kept at 5 mm. Hydrogenation processes were carried out at different temperatures of 773, 873, 973 and 1073 K. The morphology of the titanium hydrides was studied by scanning electron microscopy. The images showed an increase in the roughness titanium surface as well as the formation of cracks due to the hydride titanium precipitation. The structure of these titanium hydrides was analyzed by X-ray diffraction, performed through θ–2θ scans from 1 to 15° grazing incident angle. The results revealed that the temperature enhanced the titanium hydride concentration in the samples with a predominant precipitation of TiH phase for the four temperatures studied.