How does ion species like Argon, tungsten and Neon affect tungsten sputtering and reflection yiellds?5 answersIon species such as Argon, tungsten, and Neon play crucial roles in affecting tungsten sputtering and reflection yields. Argon atoms interacting with tungsten surfaces can lead to sputtering and material degradation events. Alternating bombardment with Argon and deuterium projectiles can predict mean sputtering yields, showing no synergistic effects in low-flux regimes. Neon seeding in fusion devices can cool plasma and protect tungsten targets, affecting sputtering rates by initially increasing and then decreasing them, showcasing a suppression effect. Calculations for beryllium and neon ions bombarding tungsten show good agreement with experiments, essential for understanding impurity supply during tokamak plasma interactions. High Power Impulse Magnetron Sputtering in Ar-Ne gas mixtures can control noble gas inclusion in tungsten coatings, with ion energy and flux influencing gas retention and film properties.
How does Argon, tungsten and Neon ions affect the sputtering yield of pristine tungsten surfaces at perpendicular incident angle?5 answersArgon, tungsten, and neon ions impact the sputtering yield of pristine tungsten surfaces at perpendicular incident angles. Research shows that nanocolumnar tungsten surfaces exhibit a significant reduction in sputter yield when bombarded by 2 keV Ar ions, with reductions of approximately 80% compared to flat surfaces. Additionally, tungsten fuzz morphology plays a crucial role in physical sputtering, with deep and relatively open recessions resulting in lower sputtering yields. Nanostructured tungsten surfaces demonstrate a reduced dependence on ion incidence angle, attributed to geometrical redeposition effects between nanocolumns, supporting their use as first wall coatings. Molecular dynamics simulations reveal good agreement with experimental data for Ne-W collisions, crucial for impurity supply calculations in fusion reactors. The sputtering yield of tungsten surfaces is also influenced by surface orientation and incoming ion angle, with different features affecting sputtering yields at specific angles.
How the microstruture affects deterium retention?5 answersThe microstructure of plasma-facing materials significantly influences deuterium retention in fusion reactor environments. Studies have shown that surface topography plays a crucial role in determining deuterium retention levels. For instance, deep surfaces inside castellation gaps exhibited significantly lower deuterium concentrations compared to areas near the exposed surface, showcasing the impact of surface topography on retention. Additionally, the density of trapping sites in materials, influenced by factors like surface treatment, impacts deuterium retention. Different surface treatments such as mechanically polished, electropolished, and recrystallized tungsten samples showed varying levels of deuterium retention, with recrystallized samples exhibiting the highest retention. Therefore, the microstructure, including surface topography and treatment, plays a crucial role in determining deuterium retention in fusion reactor materials.
Why tungsten is best for fusion radiation damage?4 answersTungsten is considered ideal for fusion radiation damage due to its high threshold energy, resistance to co-deposits with tritium, and excellent thermal properties. However, radiation damage from helium ions can alter tungsten's microstructure. To enhance tungsten's resilience, nanostructured tungsten has been developed, showing improved properties against helium ion irradiation. Experimental techniques like tungsten-ion and helium-ion implantation mimic neutron and helium irradiation, revealing detrimental effects on tungsten's mechanical properties and structural integrity. Simulating neutron irradiation through atomistic-level simulations is crucial for understanding radiation damage in tungsten. Combinatorial experiments with W-Re-Ta alloys have shown that composition variations can significantly impact the distribution of implanted helium clusters, influencing the material's damage tolerance.
How does the presence of tungsten affect the solubility of iron in aqueous solutions?5 answersThe presence of tungsten can affect the solubility of iron in aqueous solutions. In the corrosion behavior of tungsten heavy alloys, the extent of corrosion depends on the alloy composition and the pH of the medium. Tungsten heavy alloys with different compositions showed different corrosion rates in different media, with an alloy containing 93% W, 4.5% Ni, 1.0% Fe, and 1.5% Co exhibiting the lowest corrosion rate. Additionally, in the electrolyte solution for iron-tungsten plating, the dissolution of tungsten salt in the solution can lead to the deposition of iron and tungsten on the substrate. However, the specific effect of tungsten on the solubility of iron in aqueous solutions is not explicitly mentioned in the abstracts provided.
Moisture content of tungsten tailings?2 answersThe moisture content of tungsten tailings can be monitored using hyperspectral cameras to obtain a relationship between moisture content and light reflectance. This technique allows for the generation of moisture surface maps, which can be used to monitor evaporation rates and water balance in tailings storage facilities. Additionally, remote sensing has been proven to be a useful tool for inferring spatial variations in moisture content for surface tailings. Laboratory testing conducted on iron mine tailings has shown that a relationship exists between moisture content and strength for the surface of mine tailings. Spectral reflectance measurements in the solar range have also been used to estimate water content of oilsands tailings. However, it is important to note that the specific moisture content of tungsten tailings was not mentioned in the abstracts provided.