Activation characterization of a novel quinary alloy Ti-Zr-V-Hf-Nb non-evaporable getters by x-ray photoelectron spectroscopy.

The first results on the activation process and mechanisms of novel quinary alloy Ti-Zr-V-Hf-Nb non-evaporable getter (NEG) film coatings with copper substrates were presented. About 1.075 µm of Ti-Zr-V-Hf-Nb NEG film coating was deposited on the copper substrates by using the DC sputtering method. The NEG activation at 100, 150, and 180 °C, respectively, for 2 h was in situ characterized by x-ray photoelectron spectroscopy (XPS). The as-deposited NEG film mainly comprised the high valence state metallic oxides and the sub-oxides, as well as a small number of metals. The in situ XPS studies indicated that the concentrations of the high-oxidized states of Ti, Zr, V, Hf, and Nb gradually decreased and that of the lower valence metallic oxides and metallic states increased in steps, when the activation temperature increased from 100 to 180 °C. This outcome manifested that these novel quinary alloy Ti-Zr-V-Hf-Nb NEG film coatings could be activated and used for producing ultra-high vacuum.

The Characterization of Silicone-Tungsten-Based Composites as Flexible Gamma-Ray Shields.

Robots are very essential for modern nuclear power plants to monitor equipment conditions and eliminate accidents, allowing one to reduce the radiations on personnel. As a novel robot, a soft robot with the advantages of more degrees of freedom and abilities of continuously bending and twisting has been proposed and developed for applications in nuclear power industry. Considering the radiation and high-temperature environment, the overall performance improvement of the flexible materials used in the soft nuclear robot, such as the tensile property and gamma-ray shielding property, is an important issue, which should be paid attention. Here, a flexible gamma-ray shielding material silicone-W-based composites were initially doped with nano titanium oxide and prepared, with the composition of 20 silicone-(80-x) W-(x) TiO2, where x varied from 0.1 to 2.0 wt.%. Structural investigations on SEM and EDS were performed to confirm the structure of the prepared composites and prove that all the chemicals were included in the compositions. Moreover, the tensile property of the composites at 25, 100, and 150 °C were investigated to study the effect of working temperature on the flexibility of the compositions. The attenuation characteristics including the linear attenuation coefficients and mass attenuation coefficients of the prepared silicone-W or silicone-W-TiO2-based composites with respect to gamma ray were investigated. The stability of the silicone-tungsten-TiO2-based composite at high temperature was studied for the first time. In addition, the influence of nano TiO2 additive on the property's variation of silicone-W-based composites was initially studied. The comparison of the properties such as the tensile elongation, thermal stability, and gamma-ray shielding of the synthesized silicone-W and silicone-W-TiO2 composites showed that the addition of nano TiO2 powders could be useful to develop novel gamma-ray-shielding materials for radiation protection of soft robots or other applications for which soft gamma-ray-shielding materials are needed.