Electric and Adsorption Characteristics of Nanocrystalline V-(N, He) Coatings

Abstract

This paper studies the structure, temperature dependences of electric resistance, and adsorption properties of nanoporous three-component V-(N, He) coatings. The coatings were produced using the technique of ion beam assisted deposition, in particular, deposition of vanadium onto a titanium substrate simultaneously bombarding it with ions of 30 keV. It is shown, in contrast to V-N composites that have negative TCR (temperature coefficient of resistance), that the V-(N, He) coatings have negative TCR only in the temperature range of 250 to 350. A specific surface of pores and adsorption characteristics of V-(N, He) composites depend on preliminary treatment of a titanium surface. A coating deposited onto an untreated substrate has specific surface of 25.5 /g. The preliminary irradiation of titanium with beam up to a dose of 6 1017 ion/ provides the increase in surface area up to 57.6 /g. The preliminary ion bombardment provides a considerable increase in hydrogen adsorption capacity of coatings. Especially, such impact is noticeable at the room temperature, when the amount of hydrogen absorbed by a coating that was applied onto a treated surface is more than three times of that absorbed by a coating that was deposited onto nonexposed titanium.