Hideo Numata and Tokuzou Tsujimoto
National Research Institute for Metals, Tsukuba 305-0047Formation of metal-hydride (MH) on the Ti3Al surface by charging hydrogen (H) electrochemically in sulfuric acid with 0.5 g/m3 Sb2O3 as a hydrogen recombination poison has been studied by X-ray diffractometry (XRD) and thermal desorption spectrometry (TDS) combined with quadrupole mass spectrometry (QMS).
The two types of hexagonal phase were found in the XRD diagram after the cathodic charging (CP) for 1 h. The one is the a2 phase and the other is a MH phase which has lattice parameters of a=0.588 nm and c=0.794 nm.
Two peaks at 600°C and 700°C in the curves of TDS and QMS corresponded to desorption of hydrogen. The measurement of XRD after heating at various temperatures showed that the MH phase with a hexagonal structure decompose at 600°C and that the hydrogen in a2 phase discharges at 700°C.
The MH phase formed in Ti3Al is not considered to be the same substance with the hexagonal type of a MH phase formed on TiAl which was previously reported.
hydride, cathodic hydrogen charging, sulfuric acid, α2 titanium aluminide, thermal desorption spectrometry, hydrogen recombination poison