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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 163 records · Page 9

Ce post-treatment for increased corrosion resistance of AA2024-T3 anodized in tartaric-sulfuric acid

Here, the effect of a post-treatment for short time in 50 mM Ce(NO 3 ) 3 solution, with or without H 2 O 2 , on the corrosion of AA2024-T3 anodized in tartaric-sulfuric acid was investigated. Electrochemical (EIS, polarization curves) and corrosion (immersion) tests showed improved performance for samples post-treated at 50 °C in the H 2 O 2 containing solution. Microstructural characterization (SEM, STEM, GDOES) evidenced the presence of Ce oxyhydroxides both at the surface and within the pores of the anodized layer, and their preferential interaction with defective sites both at micro and nanoscale. Important amounts of Ce-species were found near corrosion products, indicating active corrosion protection by Ce ions.

36 MATERIALS SCIENCE↗

Ion irradiation effects on Cr-coated zircaloy-4 surface wettability and pool boiling critical heat flux.

The concept of coating the currently used nuclear fuel cladding (zirconium-based alloy, typically Zircaloy-4 or Zirc-4) with an oxidation preventive layer is a progressing Accident tolerant Fuel (ATF) candidate alloys. The coated Zirc-4-based alloys could be a solution to suppress undesirable fast reaction kinetics with high-temperature steam. Zirc-4 has been the most preferred cladding material in pressurized water reactors (PWRs). Chromium (Cr) based alloys as a coating material provides excellent corrosion protection and good strength and wear resistance. In this paper, we present the surface wettability measurements and pool boiling Critical Heat Flux (CHF) for Cr-coated Zirc-4 claddings pre- and post-exposure to an ion irradiation environment. The wettability measurements, including static contact angle (contact angle, θ) and average surface roughness (surface roughness, Ra), are introduced for samples of different coating thicknesses (5–30 μm thick). The coatings fabricated by the cold spray of Cr-Al particles to 10 mm × 10 mm × 1.95 mm Zirc-4 substrates. Post fabrication, a Pilgering (cold rolling) process, was applied to finalize the coating thickness and resulted in a significant reduction in surface roughness of initially fabricated rough surfaces. The process produced three distinguished samples 5-μm unpolished (as machined), 5-μm, and 30-μm polished (cold rolled). The measurements are presented for the three surfaces and bare Zirc-4 as a baseline surface. The contact angle analyses were implemented in theoretical models from the literature to predict pool boiling CHF. Pool boiling experiments were conducted to measure the pool boiling CHF values and compare them to the predicted values. Scanning Electron Microscope (SEM) images and Energy Dispersive X-ray Spectroscopy (EDS) analysis was performed to characterize the surfaces for better understanding and interpreting the results. The SEM images showed localized surface damage due to ion irradiation. No recognized change in the measured surface roughness due to ion irradiation. The contact angles of irradiated Cr-coated surfaces are consistently higher (10°) than pre-irradiated surfaces. Decreasing the Cr-coating layer thickness resulted in lower contact angle pre- and post- ion irradiation. The predicted pool boiling CHF using the Kandlikar model is in good agreement with the experimentally measured CHF values within ±12% for all samples.

36 MATERIALS SCIENCE↗

Comparison of semi-doped PANI/DBSA complex achieved by thermal doping and roll-mill process: A new perspective for application

Conductive polymers have garnered extensive attention over the last few decades owing to their vast applications and relative ease of production. One such polymer is PANI; with versatile thermo-mechanical, chemical, and electrical properties, has been researched for varied applications in the field of electronics, electrodes and corrosion protection. In this study, we focus on an alternative route to process semi-doped PANI/DBSA complexes with special focus on material properties for improved processability. This study investigates the influence of two different material preparation techniques: roll-milling and thermal-doping, on the formability and processability of such polymer-complex systems. Results confirm similar doping levels achieved in both processes and shear-thinning behavior was only observed for roll-milled samples. These results underline the formability of roll-milled PANI/DBSA with thermosetting resins. It essentially explains the production route and offers a perspective for commercial manufacturing.

36 MATERIALS SCIENCE↗

Imaging the kinetics of anisotropic dissolution of bimetallic core–shell nanocubes using graphene liquid cells

Chemical design of multicomponent nanocrystals requires atomic-level understanding of reaction kinetics. Here, we apply single-particle imaging coupled with atomistic simulation to study reaction pathways and rates of Pd@Au and Cu@Au core-shell nanocubes undergoing oxidative dissolution. Quantitative analysis of etching kinetics using in situ transmission electron microscopy (TEM) imaging reveals that the dissolution mechanism changes from predominantly edge-selective to layer-by-layer removal of Au atoms as the reaction progresses. Dissolution of the Au shell slows down when both metals are exposed, which we attribute to galvanic corrosion protection. Morphological transformations are determined by intrinsic anisotropy due to coordination-number-dependent atom removal rates and extrinsic anisotropy induced by the graphene window. Our work demonstrates that bimetallic coreshell nanocrystals are excellent probes for the local physicochemical conditions inside TEM liquid cells. Furthermore, single-particle TEM imaging and atomistic simulation of reaction trajectories can inform future design strategies for compositionally and architecturally sophisticated nanocrystals.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Complexions at the iron-magnetite interface

Synthesizing distinct phases and controlling crystalline defects are key concepts in materials design. These approaches are often decoupled, with the former grounded in equilibrium thermodynamics and the latter in nonequilibrium kinetics. By unifying them through defect phase diagrams, we can apply phase equilibrium models to thermodynamically evaluate defects—including dislocations, grain boundaries, and phase boundaries—establishing a theoretical framework linking material imperfections to properties. Using scanning transmission electron microscopy (STEM) with differential phase contrast (DPC) imaging, we achieve the simultaneous imaging of heavy Fe and light O atoms, precisely mapping the atomic structure and chemical composition at the iron-magnetite (Fe/Fe 3 O 4 ) interface. We identify a well-ordered two-layer interface-stabilized phase state (referred to as complexion) at the Fe[001]/Fe 3 O 4 [001] interface. Using density-functional theory (DFT), we explain the observed complexion and map out various interface-stabilized phases as a function of the O chemical potential. The formation of complexions increases interface adhesion by 20% and alters charge transfer between adjacent materials, impacting transport properties. Our findings highlight the potential of tunable defect-stabilized phase states as a degree of freedom in materials design, enabling optimized corrosion protection, catalysis, and redox-driven phase transitions, with applications in materials sustainability, efficient energy conversion, and green steel production.

36 MATERIALS SCIENCE↗

Stretching of immersed polyelectrolyte brushes in shear flow

In this article, the way that polymer brushes respond to shear flow has important implications in various applications, including antifouling, corrosion protection, and stimuli-responsive materials. However, there is still much to learn about the behaviours and mechanisms that govern these responses. To address this gap in knowledge, our study uses in situ X-ray reflectivity to investigate how poly(styrene sulfonate) (PSS) brushes stretch and change in different environments, such as isopropanol (a poor solvent), water (a good solvent), and aqueous solutions containing various cations (Cs + , Ba 2+ , La 3+ , and Y 3+ ). We have designed a custom apparatus that exposes the PSS brushes to both tangential shear forces from the primary flow and upward drag forces from a secondary flow. Our experimental findings clearly show that shear forces have a significant impact on how the chains in PSS brushes are arranged. At low shear rates, the tangential shear force causes the chains to tilt, leading to brush contraction. In contrast, higher shear rates generate an upward shear force that stretches and expands the chains. By analysing electron density profiles obtained from X-ray reflectivity, we gain valuable insights into how the PSS brushes respond structurally, especially the role of the diffuse layer in this dynamic behaviour. Our results highlight the importance of the initial chain configuration, which is influenced by the solvent and cations present, in shaping how polymer brushes respond to shear flow. The strength of the salt bridge network also plays a crucial role in determining how easily the brushes can stretch, with stronger networks offering more resistance to stretching. Ultimately, our study aims to enhance our understanding of polymer physics at interfaces, with a particular focus on practical applications involving polymer brushes.

36 MATERIALS SCIENCE↗

Assessment of Cold Spray Technology for Nuclear Power Applications

This report provides an overview of cold spray (CS) technology as it relates to repair and fabrication of metal alloys in the nuclear power industry. CS is a relatively new technology with applications established in other industries (e.g., aerospace, defense), and greater use of CS is anticipated within the nuclear power industry. This report is prepared in support of the United States Nuclear Regulatory Commission (NRC) Action Plan for Advanced Manufacturing Technologies (AMTs) Rev. 1, which includes objectives to identify the AMTs most likely to be used for nuclear power applications that require NRC approval, and to prepare NRC staff to review regulatory submittals containing components manufacturing using AMTs. In addition to providing an overview of CS technology, this report highlights engineering and scientific knowledge gaps of CS and rates the size of the knowledge gaps. It also assesses importance rankings of the knowledge gaps as they relate to several application categories. The application categories considered in this exercise include factory-applied CS for chloride induced stress corrosion cracking (CISCC) mitigation, field CISCC repair, light water reactor (LWR) factory structural fabrication, and LWR field dimensional restoration and corrosion protection. The combination of a knowledge gap size rating and importance ranking for an application can be used to prioritize additional data or information gathering efforts.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Atmospheric Cold Plasma Jet Coating and Surface Treatment for Improved Adhesive Bonding Performance of Dissimilar Material Joints Subject to Harsh Environmental Exposure

The program goal was the development and demonstration of a novel material coating system using an innovative atmospheric cold microwave plasma jet to enable surface functionalization for corrosion protection, wear resistance and improved bonding strength. The technical approach was directed towards proof-of-concept demonstration of advanced point-of-manufacturing material bonding to improve adhesive joint performance subject to harsh environmental exposure. The assembled team, consisting of the researchers at the University of Illinois, end-users at General Motors and small business manufacturer Starfire Industries, successfully demonstrated a single, cost-effective, high-volume production process that meets the requirements of multi-material combinations relevant to the energy-intensive transportation industry (e.g. Al-steel, Mg-steel, Al-Mg and Al-CFRP joints for body-in-white structures) while eliminating offline pretreatment for Al and Mg alloy substrates that are energy intensive, have chemical waste disposal issues, and add cost. Technical demonstration of dissimilar material joining while maintaining bonding strength and cohesion after long-duration environmental exposure was accomplished for all materials of interest. This novel approach has broad applicability for manufacturing in automotive, aerospace, marine, railcar, and specialty consumer goods, etc.

36 MATERIALS SCIENCE↗

Dynamic Binary Complexes (DBC) as Super-Adjustable Viscosity Modifiers for Hydraulic Fracturing Fluids

In the preceding project year two, we refined three DBC formulations from a selection of over 50 different chemistries. The optimization study primarily encompassed testing for (i) reversibility extent, (ii) performance in the presence of chemical additives, (iii) adhesion and friction behavior during displacement in wellbores and pipelines, (iv) corrosion protection performance, and (v) injection performance with model fracture systems at the laboratory scale. Highly promising results obtained from all these tests signify the significant potential of DBCs in enhancing hydrocarbon recovery from unconventional reservoirs. The primary activities in the third project year included publishing experimental findings across multiple articles and conducting outreach initiatives. Throughout the year, we undertook tasks such as replicating experimental results, further optimizing various formulations and their associated experimental sets, and conducting additional tests to address missing components based on reviewer feedback and suggestions. We also explored the surfactant and friction-reduction aspects of selected formulations through drag reduction tests. In addition, we constructed an improved fracturing performance setup and performed flow injection tests. The specific DBC formulations focused on during this project period were A8/B1, A12/B5, and A10/B12. We also obtained results for additional DBC formulations and a select few commercial fracturing fluids for the purpose of comparison. Within the project's scope, we aim to enhance the experimental findings with the development of various models. The first two years focused on two key aspects: (i) the creation of a high-fidelity hydraulic fracturing model for non-Newtonian fluids to gain insights into the implementation of DBC fluids in fracking environments, and (ii) the development of a multiphase flow simulator for estimating total production, fluid saturation in the reservoir, and the creation of a fracture propagation model and kinetic Monte Carlo (kMC) models for diverse applications. In the third year, we delved into the fundamental nanostructural properties of DBCs, exploring aspects such as material chemistry, pH tunability, and control of DBC formation and stability. Subsequently, in the extension year, we conducted a systematic investigation of various building blocks containing primary, secondary, and tertiary amine functional groups to understand their impact on rheological and viscoelastic properties. Furthermore, we explored a Dissipative Particle Dynamics (DPD) model to simulate self-assembly processes with precision, creating a high-fidelity representation of relevant nanostructures. The tasks performed this year with the significant results obtained have been discussed in Section 2.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Influence of Surface Treatment on the Interfacial and Mechanical Performance of Metal-Insert Overmolded Composites

Structural composites with metal inserts are gaining increasing interest enabling light weight design for energy efficiency, provide insulation, corrosion protection without compromising mechanical integrity. Such over molded metal-polymer composites show strong potential in many automotive and aerospace component parts, e.g. car bumper, chassis, door, brackets, fasteners, etc. Despite several advantages, metal-polymer dissimilar interface remains a weak spot in structural design, requiring further investigation to improve interfacial interlocking. The current work focuses on enhancing the metal-polymer adhesion between stainless steel inserts and polymer matrices (e.g. acrylonitrile butadiene styrene resin (ABS), and polyamide 66 (PA66) through surface treatment via chemical etching and mechanical roughening. In the chemical etching process, metal substrates were treated with aqua regia solution for different time intervals to evaluate surface roughness measured by water contact angle and morphology analysis. For mechanical roughening approach, metal inserts were subjected to blasting for surface abrasion. Treated samples were also functionalized with aminosilane coupling agent which showed successful grafting on the surface measured by water contact angle. Metal inserts with micro level surface roughness through etching exhibited significant 21% improvement in adhesion strength compared to untreated inserts; however, the effect of silane treatment on the interfacial strength was found to be highly matrix dependent.

Saha, Subhabrata [ORNL] (ORCID:000000033966064X)↗

Surface-Tailoring and Morphology Control as Strategies for Sustainable Development in Transport Sector

Surface wetting plays an important role in the corrosion protection processes of aerospace applications. Here, we demonstrate the use of ultrafast femtosecond (fs) laser processing techniques to tailor the wetting properties of aluminum (Al) substrates by creating diverse surface morphologies. Specifically, two distinct laser scanning methods—dot-hatching and cross-hatching—were employed to fabricate microstructures on the substrates. By varying the incident laser parameters, we confirmed that the resulting surface morphologies exhibit different wetting behaviors, spanning from hydrophilicity to hydrophobicity. Furthermore, time-resolved spreading tests validate that dynamic wetting behaviors can also be modified. This fs laser processing approach provides a straightforward, one-step fabrication method for effectively modifying the wetting properties of Al alloys.

de Almeida Prado, Luis Antonio Sanchez↗

Pulse Electrodeposition for Carbonate-Rich Deposits from Seawater

Seawater electrodeposition is gaining renewed interest in the context of sustainable development, both to build climate-resilient coastal infrastructure and for ocean-based decarbonization applications. Most of the applications benefit from CaCO 3 -rich deposits, but constant-voltage electrodeposition results in a mixture of CaCO 3 and Mg(OH) 2 , especially at higher voltages where precipitation rates are more desirable. The use of pulse voltages can help control interfacial pH that dictates the precipitation reactions. Here, we explore the use of pulse electrodeposition as a function of pulse frequency and duty cycle to control deposit composition. The most CaCO 3 -rich deposits were obtained under 10 Hz frequency and 10% duty cycle conditions for the voltage window investigated (-0.8 V to -1.2 V vs. SCE). While pulsing the voltage increases the amount of CaCO 3 deposited, the energy required per gram of CaCO 3 is significantly higher (14.5×) when compared to the base case of applying a constant voltage of -0.8 V vs. SCE. Further optimization of pulse conditions, electrode materials, and system configuration could lead to finding parameters that result in exclusively carbonate deposits without compromising precipitation rates, which may prove to be more useful for corrosion protection, coastal infrastructure, and other applications in sustainable development.

54 ENVIRONMENTAL SCIENCES↗

Parallel-gap welding for joints between copper conductors and Kovar

Welding technique produces more reliable joints than soldering. Investigation used different sizes of copper conductors and component lead ribbons, corrosion protection platings, and melting points of metals being joined. Optimum combination is gold-plated component lead ribbons and solder-plated copper conductors.

Mc Daniel, G. E.↗

Zinc-rich coatings: A market survey

Zinc-rich coatings with both organic and inorganic binders were considered for coastal bridges which require more corrosion protection than inland bridges because of exposure to salt spray and fog. Inorganics give longer protection and may be applied without a finish coat; those currently available are harder to apply than organics. The NASA potassium silicate/zinc - dust coating appears to provide longer protection, resist thermal shock, and overcome the application problem. Panels coated with the formulation withstood 5308 hours in a salt spray chamber with no rusting or blistering.

Lizak, R.↗

Further development of a biocide generation and water system passification system addendum

An electrochemical process for generating iodine in situ in a potable water metallic storage system was examined. The degree of concurrent corrosion protection and of metallic ion buildup was determined. A working metal bellows system was evaluated and tested for the buildup of metallic ions comparable to that reported in spacecraft potable water specifications. An integrated system was assembled and tested which may be used to maintain the potability of water which is passively stored in metallic containers for extended periods of time. Test conditions and apparatus are described.

Source record↗

Vapor corrosion inhibitors

Report describes effectiveness and materials compatibility of amine nitrites. Particularly of value to those interested in long-term corrosion protection.

Bielman, L. A.↗

Low toxic corrosion inhibitors for aluminum in fresh water

Combinations of chemical compounds that reportedly reduce the corrosion of aluminum in fresh water were evaluated. These included combinations of borates, nitrates, nitrites, phosphates, silicates, and mercaptobenzothiazole. Eight of fifty inhibitor combinations evaluated gave excellent corrosion protection and compared favorably with sodium chromate, which has generally been considered standard for many years.

Humphries, T. S.↗