| Author(s): | I. B. SAVVATIMOVA
FSUI, SRI, SFA, “Lutch”, Russia
D. V. GAVRITENKOV
FSUI, SRI, SFA, “Lutch”, Russia
|
| Abstract: | In this study, we report on the surface structure, distribution, and isotopic composition of elements found on Ti cathodes before and after glow discharge in plasma, during which excess heat was produced. Irradiation was carried out with deuterium ions with a discharge voltage below 1000 V, with a current of 10–20 mA. The analysis of the surface structure and of elemental composition of the Ti sample was carried out with a scanning electron microscope with Energy Dispersive X-ray Spectroscopy (EDS), which can detect impurities at concentrations as low as 0.2 at.%. New metallic phase formation and newly present elements were revealed by the EDS method in several different, separate active spots on the cathode surface, with concentrations ranging from 0.3 up to 10 or 20% or more. Al, Mg, Br, and Sr were found at ~0.3%, Rb ~0.4%, S ~1.0%, F ~10%, O >20%, Ni ~0.3–20%, Cr ~1.4%, Fe ~4.0%, and Sn ~0.4–5.0% were detected by this method after the experiment and were not in the as-received sample before the experiment. The basic changes are observed in places of microexplosions, micromeltings, and structural inhomogeneities. Investigation of the isotopic composition was carried out by Thermal Ionization Mass Spectroscopy (TIMS). Additional elements in a thin surface layer were found by this method when analysis was performed at 1900°C. The Ti cathode produced excess heat during glow discharge, estimated at 10–20% above input power. This suggests that the heat was caused by the formation of the observed new elements. It is necessary to note that excess heat was created by the processes in a sample having weight of 0.7 g in a device weighing 5 kg. At the same time thermal losses with the water-cooling of anode, losses through a quartz wall of the discharge chamber and the losses in metal flanges were not taken into account. In the experiments with other cathode materials (including Mo, W, and Zr) under the same experimental conditions, no excess heat was observed and thermal losses were roughly 40%. |
