Layered Composite Hydrogenated Films of Zirconium and Niobium: Production Method and Testing Using Thermo EMF (Thermoelectric Method)

Abstract

Layered materials incorporating hydrogen were obtained using Nb/Zr films with varying numbers of layers from 50 to 100. The films were deposited on a silicon substrate using a vacuum magnetron sputtering method on a dedicated setup. The film thickness varied from 10 to 50 nm. The resulting material was hydrogenated with protons on a TPU electrostatic generator with an energy of up to 1.2 MeV. The deposition modes for nanoscale metallic multilayer Zr/Nb systems were determined: for a Zr target the specific power of the sputtering system was 37.9 W/cm², and for a Nb target it was 26.4 W/cm². A coating with clear boundaries between individual layers of zirconium and niobium was obtained. It was shown that the optimal conditions for studying nanoscale Zr/Nb layers are a pressure of 700 Pa, a power of 40 W, a frequency of 2 kHz, and a plasma filling factor of 12.5% for coatings with individual layer thicknesses of 100 nm. For coatings with layer thicknesses from 10 to 50 nm, the optimal conditions are a pressure of 650 Pa, a power of 40 W, and a frequency of 1 kHz. The thermo EMF method (GOST (State Standard) 25315–82) was used for testing. It was found out that after proton irradiation, an intensive accumulation of hydrogen atoms occurs near the interfaces; it reduces the structure defectiveness and entails a change in the thermo EMF up to the inversion of its sign. The hydrogen distribution is predominantly bimodal, with local maxima in hydrogen concentration observed at the Nb/Zr interfaces, while accumulation at the Zr/Nb interface is considerably lower. Hydrogen localization near interfaces primarily occurs around zirconium.