X-ray study of the precipitation of hydrogen in vanadium

Abstract

Many anomalies have been reported for the behavior of vanadium at low temperatura. In particular, Colella, Batterman and Kashyap during the study of the x ray diffuse scattering in vanadium single crystals have observed an extra scattering at low temperature in certain regions of reciprocal space. Westlake pointed out that vanadium getters considerable amounts of hydrogen in very common laboratory operations such as mechanical, chemical, and electrochemical polishing. Then, supposedly "pure" vanadium can actually be a vanadium-hydrogen alloy. On this basis most of the reported anomalies.can be explained in terms of the precipitation of second phase which is predicted from the equilibrium diagram for the vanadium hydrogen system. Taking into account Westlake's results, Colella, Batterman and Kashyap attributed the low temperature extra scattering to hydrogen impurities. This was borne out experimentally since the extra scattering disappeared after thecrystals were given the particular vacuum anneal which is known to remove dissolved hydrogen.