钛-氢体系的物理化学性质

Physical and Chemical Properties of Titanium-Hydrogen System

综合评述了钛-氢体系的物理化学性质。钛是一种具有同素异型转变点Tc(1155K)的吸氢金属,氢在α钛和β钛中有不同的溶解度,在Tc以下易形成具有面心立方晶格结构的Ti H2,氢原子溶解在晶格中,占据四面体间隙位(T)。钛加热吸氢时晶格发生膨胀,产生体胀效应,当温度降低时氢化物又会沿惯习面发生偏析。氢在钛中的扩散在高温时表现为正常扩散即lnD与1/T呈直线关系,在低温时存在隧道扩散。钛-氢体系的热力学p-c-T曲线表现出良好的平台性且在高于593K时存在两个平台。测定了钛-氢体系的反应的动力学扩散活化能和表观活化能。

The physical and chemical properties of Ti-H system are reviewed. There is an allotropic change temperature（1155K） for pure Ti and it is a hydrogen-absorbing metal for different solubility in α-phase titanium and β- phase titanium. The hydrogen atom dissolves in lattice and occupies tetrahedron interstitial position, and then forms TiH2 sublattice of face-centered cubic. Upon hydrogen absorption, the lattice undergoes an expansion while retaining its fcc structure and then hydride will have segregation when temperature falling. There is a linear relation between the diffusion factor＇s logarithm and absolute temperature＇ s reciprocal because the diffusion path of hydrogen is natural jumping at high temperature and there is a tunnel diffusion at low temperature. The pressure-composition-temperature curves in titanium-hydrogen system exhibit good plateau and there are two plateaus when temperature exceeds 593K. The activation energy values are also researched.