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Abstract not provided.
Systems and methods for coating a metallic component are provided. In one embodiment, a metallic coating may be disposed in a plating bath comprising AlBr3. The metallic coating may be coupled with, or configured as, a working electrode. A counter electrode formed of aluminum may be disposed within the plating bath. An electric current may be applied between the two electrodes resulting in the electrodeposition of aluminum on the metallic component. In one particular embodiment, the plating bath may include LiBr, KBr and CsBr, with AlBr3 being present in an amount of approximately 80 percent or greater by weight. Various types of metals may be coated with aluminum using embodiments of the present disclosure. Additionally, the methods and systems described herein are amenable to coating of complex geometries.
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Current structural alloys, code certified for the MSRs temperature ranges, contain high levels of chromium, making them highly susceptible to molten halide salt corrosion. One potential solution to circumvent the need for code certification of novel alloys, which is expensive and time consuming, is to design claddings that will protect the underlying code certified materials from corrosion damage during operation. In this work, we examined the corrosion of Ni and Cu electroplated, Ni and CuNi weld overlay, Mo-laser clad, and carburized claddings on SS316H for use in molten salt reactor environments. After characterization of the cladded materials (Task 1), static corrosion tests were used to assess corrosion resistance of the claddings in typical molten fluoride salts (Task 2). The corrosion tests were performed in molten FLiNaK at 700°C up to 1000 hours. Pre- and post-corrosion Scanning Electron Microscopy (SEM), energy-dispersive-spectroscopy (EDS), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and glow-discharge-optical-emission-spectroscopy (GDOES) were performed on cladding cross-sections and surfaces to evaluate degradation. The Cu and Ni electroplated samples, as well as the carburized samples, showed excellent corrosion resistance relative to the bare SS316H. To assess high temperature cladding stability, ageing experiments were performed at temperatures up to 900 C in inert atmosphere for the electroplated and carburized samples and a diffusion model was developed to predict long term cladding behavior (Task 3). It was found that the Cu cladding was basically insensitive to the high temperature ageing, except for small secondary phases forming at the interface. On the other hand, the Ni electroplated cladding experienced significant interdiffusion. Nevertheless, the gain in corrosion resistance for a 100μm Ni electroplated cladding is phenomenal, with more than 50% reduction in chromium dissolution from the substrate material for the first 15 years of salt exposure at 700°C. To assess radiation resistance and phase stability, high-temperature 4MeV Ni heavy ion irradiation was performed across the cladding/substrate interface up to 50 displacement-per-atom (DPA) at 500°C and 700°C to assess the phase stability and irradiation behaviors of the electroplated systems (Task 4). The Ni and Cu electroplated systems did not experience void swelling at the contrary to the SS316H substrate due to their nanocrystalline nature. Some level of recrystallization was observed in the cladding, as well as radiation induced segregation and enhanced diffusion. The interface acted as a potent sink for point defects with the presence of a void denuded zone. The mechanical properties of the claddings were assessed using thermal shock, micro-indentation, nano-indentation, and four-point bend testing experiments (Task 5). These experiments were performed on the claddings in as-received, corroded, irradiated, and thermally aged states to determine the effects of typical molten salt reactor environments on cladding integrity. No significant mass loss was observed after repeated thermal shocks. While the electroplated samples softened after high-temperature ageing, irradiation hardening compensate this effect, such that there is little different with the as-received materials. The results of these experiments suggest that the electroplated (copper/nickel) show the greatest promise for application in molten salt reactor development. These claddings prevented any chromium dissolution from occurring during the static corrosion experiments. Additionally, they demonstrated favorable properties for high temperature diffusion, phase stability, interfacial mechanical properties, and irradiation resistance. Weld-overlay cladding are also of great interest and could reach properties similar to the electroplated samples upon optimization (especially with multiple weld passes). The carburized SS316H showed excellent behavior as well, but more work needs to be done to assess their long-term stability. Finally, the Mo-laser clad system was not pursued further due to the manufacturing challenges. It is also worth noting that the Ni cladding systems should behave relatively well in terms of weldability since the Ni-weld overlay microstructure and associated corrosion rate are sound. While the NiCu weld-overlay has even lower corrosion rates than the Ni-weld overlay, more studies on welding of Cu-electroplated systems are necessary since Cu clusters are known to embrittle steels.
Mg 2+ electroplating has been an obstacle for Mg metal batteries due to the passivating nature of Mg metal. Here, a unique current collector based on an amorphous MgO-wrapped Zn-skeleton enabled Mg 2+ electroplating for a high-voltage Mg metal battery.
Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.
Arrays of superconducting transition-edge sensors (TES) can provide high spatial and energy resolution necessary for x-ray astronomy. High quantum efficiency and uniformity of response can be achieved with a suitable absorber material, in which absorber x-ray stopping power, heat capacity, and thermal conductivity are relevant parameters. Here we compare these parameters for bismuth and gold. We have fabricated electroplated gold, electroplated gold/electroplated bismuth, and evaporated gold/evaporated bismuth 8x8 absorber arrays and find that a correlation exists between the residual resistance ratio (RRR) and thin film microstructure. This finding indicates that we can tailor absorber material conductivity via microstructure alteration, so as to permit absorber thermalization on timescales suitable for high energy resolution x-ray microcalorimetry. We show that by incorporating absorbers possessing large grain size, including electroplated gold and electroplated gold/electroplated bismuth, into our current Mo/Au TES, devices with tunable heat capacity and energy resolution of 2.3 eV (gold) and 2.1 eV (gold/bismuth) FWHM at 6 keV have been fabricated.
Lithium (Li) metal battery technology, renowned for its high energy density, faces practical challenges, particularly concerning large volume change and cell swelling. Despite the profound impact of external pressure on cell performance, there is a notable gap in research regarding the interplay between external pressure and the electroplating behaviours of Li+ in large-format pouch cells. Here we delve into the impact of externally applied pressure on electroplating and stripping of Li in 350 Wh kg –1 pouch cells. Employing a hybrid design, we monitor and quantify self-generated pressures, correlating them with observed charge–discharge processes. A two-stage cycling process is proposed, revealing controlled pouch cell swelling of less than 10%, comparable to state-of-the-art Li-ion batteries. Finally, the pressure distribution across the cell surface unveils a complex Li+ detour behaviour during electroplating, highlighting the need for innovative strategies to address uneven Li plating and enhance Li metal battery technology.
Due to its unique physical and chemical properties, bismuth is an attractive candidate for a wide range of applications such as battery anodes, radiation shielding, and semiconductors, to name a few. This work presents the electrodeposition of mechanically stable and homogenous bismuth films at micron-scale thicknesses. A simple one-step electrodeposition process using either a pulse/reverse or direct current source yielded thick, homogenous, and mechanically stable bismuth films. Morphology, electrochemical behavior, adhesion, and mechanical stability of bismuth coatings plated with varying parameters were characterized via optical profilometry, cyclic voltammetry, electron microscopy, and tribology. Scratch testing on thick electroplated coatings (> 100 µm) revealed similar wear resistance properties between the pulse/reverse plated and direct current electroplated films. This study presents a versatile bismuth electroplating process with the possibility to replace lead in radiation shields with an inexpensive, non-toxic metal, or to make industrially relevant electrocatalytic devices.
A low cost, effective slicing method is essential to make ingot technology viable for photovoltaics in terrestrial applications. The fixed abrasive slicing technique (FAST) combines the advantages of the three commercially developed techniques. In its development stage FAST demonstrated cutting effectiveness of 10 cm and 15 cm diameter workpieces. Wire blade development is still the critical element for commercialization of FAST technology. Both impregnated and electroplated wire blades have been developed; techniques have been developed to fix diamonds only in the cutting edge of the wire. Electroplated wires show the most near term promise and this approach is emphasized. With plated wires it has been possible to control the size and shape of the electroplating, it is expected that this feature reduces kerf and prolongs the life of the wirepack.
The development of a low cost and reliable contact system for solar cells and the fabrication of several solar cell modules using ultrasonic bonding for the interconnection of cells and ethylene vinyl acetate as the potting material for module encapsulation are examined. The cells in the modules were made from dendritic web silicon. To reduce cost, the electroplated layer of silver was replaced with an electroplated layer of copper. The modules that were fabricated used the evaporated Ti, Pd, Ag and electroplated Cu (TiPdAg/Cu) system. Adherence of Ni to Si is improved if a nickel silicide can be formed by heat treatment. The effectiveness of Ni as a diffusion barrier to Cu and the ease with which nickel silicide is formed is discussed. The fabrication of three modules using dendritic web silicon and employing ultrasonic bonding for interconnecting calls and ethylene vinyl acetate as the potting material is examined.
Two experimental contact systems were examined and compared to a baseline contact system consisting of evaporated layers of titanium, palladium, and silver and an electroplated layer of copper. The first experimental contact system consisted of evaporated layers of titanium, nickel, and copper and an electroplated layer of copper. This system performed as well as the baseline system in all respects, including its response to temperature stress tests, to a humidity test, and to an accelerated aging test. In addition, the cost of this system is estimated to be only 43 percent of the cost of the baseline system at a production level of 25 MW/year. The second experimental contact system consisted of evaporated layers of nickel and copper and an electroplated layer of copper. Cells with this system show serious degradation in a temperature stress test at 350 C for 30 minutes. Auger electron spectroscopy was used to show that the evaporated nickel layer is not an adequate barrier to copper diffusion even at temperatures as low as 250 C. This fact brings into question the long-term reliability of this contact system.
Mirrors fabrication for large aperture telescopes is an important aspect in space exploration programs. One of the cost effective techniques to obtain such mirrors is electroplating of Ni-Co alloys from sulfamate solution. The Center for Irradiation of Materials at Alabama A&M University - Research Institute has been involved in a NASA-MSFC project for producing ultra-light Ni-Co alloy mirrors since the summer of year 2000. The goal of this project is to obtain ultra-light, high strength electroformed large aperture normal incidence replicated mirrors, (weighting less than 5 kg/m2), free of stress, with a good figure and reproducible thickness variation. In order to simplify the control of parameters such as temperature gradient, concentration gradient, distribution of the electric field lines and flow control, the proposed geometry involves a cylindrical main tank contained in another cylindrical tank, which plays the role of a weir. Designs were created to accommodate the new horizontal position of the mandrel and the pipes fitting through the outer tank's lid. The inner tank contains the working electrodes and a series of sensors for monitoring temperature, flow, stress and pH. The outer tank holds the electric heaters, the filters and a part of the piping system. Another two tanks complete the setup and serve for rinsing/preheating and equilibrating the electroplating bath. This paper will describe advantages of the new experimental setup and the parameters achieved in the electroplating bath for the proposed geometry.
The Advanced Telescope for High ENergy Astrophysics (ATHENA) mission requires high quantum efficiency (QE) x-ray absorption, >90.6% at 7 keV and low specific heat capacity, 0.731 pJ/K. The designed ATHENA x-ray absorbers are cantilevered square tiles (pitch of 317 microns) of 1.05 μm thick Au and 5.51 μm thick Bi electroplated films supported by stems that connect the absorber to the detector below. We discuss some of the methods used to produce x-ray absorbers meeting these specifications for ATHENA. To tune the thermal conductance of the device and the effect on the normal-to superconducting transition shape, the stems need to be small diameter and can have a weak bottle-neck connection to the substrate. A funnel shape of the stem using a proximity exposed photoresist mold has been developed to improve the strength of the connections. Further requirements on the absorbers include low levels of fine particulate remaining on the substrate after production and zero shorts between absorbers due to incomplete ion milling or trapped fine particular between absorbers. To optimize for post patterning substrate cleanliness and absorber yield, we have examined several methods of absorber fabrication. Three such methods are 1) an ion mill/wet etch combination, 2) a photoresist mold for electroplating followed by wet or dry etch to remove the seed layer, and 3) an electroplating process with leveling to smooth the surface followed by ion mill to separate the absorbers. The different combinations of wet and dry etches lead to different yields and surface appearance of the absorber sidewalls. We present results on the achieved pixel yields and the energy resolution of pixels made with the various fabrication methods. We discuss the impact of absorber patterning method on performance, uniformity, and yield.
Clean materials are required to construct and operate many low-background physics experiments. High-purity copper has found broad use because of its physical properties and availability. In this paper, we describe methods to assay and mitigate Pb-210 contamination on copper surfaces, such as from exposure to environmental radon or coming from bulk impurities. We evaluated the efficacy of wet etching on commercial samples and observed that Po-210 contamination from the copper bulk does not readily pass into solution. During the etch, the polonium appears to trap at the copper-etchant boundary, such that it is effectively concentrated at the copper surface. We observed a different behavior for Pb-210; high-sensitivity measurements of the alpha emissivity versus time indicate the lowest level of Pb-210 contamination ever reported for a commercial copper surface: 0 +/- 12 nBq/cm2 (1-sigma). Additionally, we have demonstrated the effectiveness of mitigating trace Pb-210 and Po-210 surface backgrounds using custom, high-purity electroplating techniques. These approaches were evaluated utilizing assays performed with an XIA UltraLo-1800 alpha spectrometer.