This paper describes the effects of nitrogen ion implantion on the hydrogen absorption of transition metals of the IVa- and Va groups such as Ti, Zr, V, Nb, and (α+β) type Ti-6Al-4V alloy. Hydrogen charging was carried out by cathodic electrolysis, and the distribution of hydrogen concentration was obtained by glow discharge spectroscopy (GDS). Changes in structure produced by hydrogen absorption were investigated using X-ray diffraction (XRD). Results are as follows.
(1) The hydrogen absorption behavior of Ti and Zr showed a gradual retardation effect as nitrogen ion dosage increased. Hydrogen absorption to V and Nb in the V-group transition metals having a large hydrogen solubility was markedly retarded even at low-dose implantation, and no hydride was formed.
(2) This retardation of hydrogen absorption suggests that hydrogen diffusion paths were blocked by fine layers of precipitated nitrides formed by the nitrogen implantation.
(3) Hydrogen absorption to Ti alloy was improved by implantation at dosages in excess of 3×1017ions cm-2. It is considered highly probable that V and Al bonded with the implanted nitrogen to form nitride, and that such nitrides contribute to the retardation of hydrogen absorption.
