Control of nitrogen concentration in liquid lithium by iron–titanium alloy

Reducing the nitrogen concentration in liquid lithium is one of the most important steps in creating a liquid lithium blanket system. In this study, in order to verify the nitrogen gettering performance of Fe–Ti alloy, the variation in the nitrogen concentration in liquid lithium, into which Fe–10 at.% Ti or Fe–5 at.% Ti getter was immersed, was examined. The results confirmed a gettering performance of Fe–Ti alloy comparable to that of V–Ti alloy, although the effects were not durable in either the Fe–Ti or the V–Ti alloy. After the immersion test, the existing states of nitrogen absorbed in the gettering material were analyzed by means of XRD, XMA and XPS. TiN and some nitrogen dissolved in α-Fe without forming TiN were observed. It was indicated that nitrogen gettering is prevented not only by the surface nitrides, but also by the internal diffusion barriers originating from the absorbed nitrogen.