Hydrogen Isotope Effects of Ti, Zr Metals

The p-c-T curves of D₂ and T₂ absorption by Ti and Zr were measured. there are one plateau at temperature below 300 °C and two plateaus at temperature range of 500~600 °C for Ti but one plateau below 525°C and two plateaus above 525°C for Zr. The thermodynamic parameters on different phases were determined and there are obvious thermodynamic isotope effects. The lag effect was not observed for Ti but its existent for Zr. The kinetic p-t curves of absorption were investigated at different temperature ranges and then the rate constants are calculated. The results show that the rate constants increase with raising temperature for Ti but decrease for Zr. The activation energy values are (110.2±3.0), (155.7±3.2) kJ.mol^-1 respectively for Ti and (-25.9±0.7), (-6.8±0.8) kJ.mol^-1 for Zr. The kinetic p-t curves of desorption were investigated too and the activation energy of desorption are (42.3±1.9), (62.1±1.6) kJ.mol^-1 respectively for Ti and (40.1±0.8), (57.7±1.6) kJ.mol^-1 for Zr. So there are remarkable kinetic isotope effects for Ti, Zr.