Kinetic Studies on the Hafnium and Deuterium
Abstract
Through the method of reaction rate analysis in a constant volume reactor,the time dependence of the pressure drop of the hafnium deuteride formation are studied over a temperature range 573～873 K on a metal hydride thermodynamic and kinetic parameters measuring apparatus.The rate constants of the hafnium deuteride formation,which are 0.053 0 s-1,0.045 2 s-1,0.031 9 s-1,0.026 1 s-1,are calculated at a serial temperatures of 573 K,673 K,773 K,873 K and the initial pressure of 13 kPa.The activation energy of the reaction is(-10.1±1.5)kJ·mol-1.Comparing the above results with those of titanium deuteride formation on the same measuring apparatus,the kinetic mechanism of the deuteride formation of hafnium and titanium is considerd different.It is concluded that the reaction rate of hafnium absorbing deuterium may be controlled by phase transformation and surface oxidation.