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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Methods of removing a ceramic coating from a substrate

A method for removing a ceramic coating from a substrate is presented. The method includes contacting the ceramic coating with a composition including a fluoride source and nitric acid. A method of forming a component having a variation in saturation magnetization is presented. The method includes masking selected portions of a surface of a metallic component using a ceramic coating to form a masked metallic component; selectively diffusing nitrogen into the metallic component by exposing the masked metallic component to a nitrogen-rich atmosphere; and removing the ceramic coating from the surface of the metallic component by contacting the ceramic coating with a composition including the fluoride source and nitric acid.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Biocompatibility of a novel heat-treated and ceramic-coated magnesium alloy (Mg–1.2Zn–0.5Ca–0.5Mn) for resorbable skeletal fixation devices

Our recent exploration into the use of biodegradable metals and surface treatments resulting in sufficient strength for skeletal reconstruction applications has led to the need to test these devices’ cytotoxicity. More specifically, our group has developed a resorbable magnesium alloy, Mg–1.2Zn–0.5Ca–0.5Mn, that can be strengthened by heat treatment and coated with a ceramic layer offering time-certain resorption of a medical device. This in vitro study shows that these treatments do not result in cytotoxicity. Both heat-treated (HT) and HT + ceramic-coated (sol–gel) coupons demonstrated more than 70% viability. Thus, these processing steps are likely to be useful in producing biocompatible, resorbable implants that incorporate our Mg–1.2Zn–0.5Ca–0.5Mn alloy.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Status Report on Ion Irradiation Study of Ceramic Coating in Suppressing Fuel/Cladding Chemical Interaction

Advanced cladding is critical for the development of advanced nuclear reactors with enhanced performance in radiation tolerance and neutron transparency. It will ensure adequate thermal conductivity and mechanical stability of cladding base material, corrosion resistance and high temperature coolant compatibility of cladding surface. Finally, it provides chemical stability in the cladding inner wall against fuel/cladding chemical interaction (FCCI). An innovative cladding with a three-layer structure (i.e., a treated surface, a base material, and a treated inner-wall) promises to meet all the listed requirements. The initial work on innovative researching and developing these cladding materials seeks to demonstrate the effectiveness of a thin ceramic coating in suppressing FCCI through ion-irradiation. It consists of a study of Ce/TiN/Fe diffusion couples. This report provides an update on the status of ceramic-coating preparation and the testing of diffusion couple samples, the design of an ion-irradiation experiment, and characterization of the microstructure of a legacy-coupon sample coated with 1 µm of TiN and irradiated with 5 MeV Fe ions to 200 dpa at 500°C.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Summary Report on Ion Irradiation Study of Ceramic Coating on Suppressing FCCI

Advanced cladding is critical for advanced nuclear reactors with an enhanced performance in radiation tolerance and neutron transparency. Using advanced cladding will ensure the adequate thermal conductivity and mechanical stability of the cladding base material, corrosion resistance, high-temperature coolant compatibility of the cladding surface, and chemical stability in the cladding inner wall against fuel cladding chemical interaction (FCCI). An innovative cladding with a three-layer structure (i.e., a modified surface, a clad base material, and a modified inner wall) promises to meet all these requirements. Initial research and development (R&D) regarding this innovative cladding seek to demonstrate the effectiveness of a thin ceramic coating in suppressing FCCI under ion irradiation to high dose. This United States (U.S.) Department of Energy (DOE)–Office of Nuclear Energy (NE) project report summarizes the results of recent ion irradiation studies of diffusion-couple samples with details of an ion irradiation experiment, the characterization of the interface microstructure of cerium (Ce)/titanium nitride (TiN)/oxide-dispersion strengthened (ODS), Ce/TiN/iron (Fe), Ce/ODS, and Ce/Fe samples irradiated with 80 million electron-volts (MeV) of xenon (Xe) ions to 100 displacements per atom (dpa) at 500?C using the Argonne Tandem Linac Accelerator System (ATLAS) facility at Argonne National Laboratory (ANL). The results of the ODS-substrate sample are encouraging and demonstrate the effectiveness of a thin ceramic coating on FCCI mitigation under irradiation. The results from an Fe-substrate sample revealed a complex microstructure, and the root cause is discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Recipe for coating ceramic blades for ion trapping

The first batches of ion traps patterned and coated were processed per the standard 3-step clean, air fire, and metallization processes. The third or fourth lot using this process resulted in poorly adhering metallization. Up until this point, the standard process was used to metallize and pattern ceramic ion traps without fail. At about the 4th batch of parts something changed. After the 5th batch, the ceramic ion traps received generally came with some unknown contamination that does not come off in a standard 3-step clean (Lenium Vapor Degreaser, Acetone, IPA) and air fire (860C for 1 hour) for which this process removes the vast majority of all contamination for most ceramic metallization. This is highly unusual. Using HF + Boiling H 2 O 2 is extreme for cleaning the ceramic ion traps. The contamination was never identified and is stubborn to effectively clean. Standard as-fired ceramic should be very easy to clean as if s fired at temperatures greater than 1400°C and not much in terms of contamination should exist at these temperatures, so there must be an intermediate step/process which is imparting this contamination. It is likely a polishing compound or previous polishing contaminant, but also not easily visually distinguishable until after metallization. The halo marks observed on parts might be fingerprints (less likely) or potential polishing marks (more likely) as metallization typically doesn't cover/hide any damage or contamination, but rather quite clearly the opposite, it accentuates it. Blotchy appearances in the metallization usually indicated an adhesion issue. As a result of the fragility of the parts (yield loss due to handling) and difficulty in identifying the contamination during cleaning, we have taken a conservative approach of HF + H 2 O 2 cleaning for all batches after the contamination and adhesion issues were identified.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Understanding and Controlling Toughening Mechanisms in Nanotube Reinforced Ceramic Coatings (Final Report)

Research in this program is designed to understand mechanical behavior, particularly fracture toughness, in ceramics that are reinforced with carbon nanotubes (CNTs). In the past four years, emphasis was placed on: Synthesizing and characterizing ceramic nanocomposite materials reinforced with both multiwall carbon nanotubes (MWNTs) and single wall nanotubes (SWNTs) and implementation and analysis of in situ mechanical testing methods to better understand and engineer the critical CNT/ceramic interfaces.

36 MATERIALS SCIENCE↗
DOE OSTI2021

High-Entropy Ceramic Coatings: Transformative New Materials for Environmentally-Compatible Thin-Film Insulators against High-T Molten Salts

An emerging new class of promising materials, High-Entropy Ceramics (HECs) or Compositionally-Complex Ceramics (CCCs), have been successfully fabricated in the last three years. This project evaluates HECs/CCCs in the concentrated solar power (CSP) context. In this project, we have identified a couple of simple, and key descriptors governing thermal conductivity in HECs. Size disorder among the cations was found to have a strong influence on the thermal conductivity across multiple systems and throughout a vast compositional space. Since identifying this, we have optimized previous compositions to achieve low thermal conductivities of $k$~$1-1.4Wm{-1}K{-1}$. We have further reduced our selection of promising compositions based on project guidelines and applied a theory that can potentially predict reactivity with molten salts to identify a small set of HECs that are suitable for further molten salt heat transfer media (HTM) stability testing. Many compositions reveal poor resistance to molten chloride salt after being exposed for 24 h compared to the reference structural alloy, Haynes 230. However, after 100 h, a few HECs/CCCs show strong parabolic rate constant effects and provide greater resistance to chloride salt compared to Haynes 230 alloy, which shows more linear kinetics. Postmortem characterization of the microstructure reveals the parabolic rate constant originates from a dense reaction layer form at the interface. This feature is absent in Haynes 230, which only shows grain boundary infiltration. The HECs/CCCs were also put in contact with the metal alloy under Ar for 800 h at 800°C and show negligible interaction. Lastly, parabolic rate constant HECs/CCCs also have low thermal conductivity $(<2 Wm^{-1} K^{-1})$ at 800°C. These specimens satisfy all project requirements and demonstrate their promising application in next-generation CSP.

14 SOLAR ENERGY↗
DOE OSTI2018

Functional Plasma-Sprayed Ceramic Coatings for Use in Fusion Energy Systems

There is growing demand for new, cleaner ways to supply the rapidly growing global energy demand, as concerns grow over climate change and declining supplies of fossil fuels. Nuclear fusion, the phenomenon in which atomic nuclei collide together and release massive quantities of energy, is one of the most promising options for generating large amounts of carbon-free energy in the future.1 To initiate a common nuclear fusion reaction of hydrogen isotopes – deuterium and tritium, a hot plasma state is needed at incredibly high temperatures approaching 100 million degrees centigrade. One practical way to achieve these conditions is to use magnetic confinement of the plasma in a toroidal nuclear reactor known as a tokamak (Figure 1). A commercial fusion power station will then harvest the energy by converting the heat provided by the fusion chain reaction into steam to power gas turbines, and generate electricity on to the grid, while the excess neutrons also produced in the process is captured by a blanket made of dense material surrounding the tokomak.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Environmental degradation of high-temperature protective coatings for ceramic-matrix composites in gas-turbine engines

Abstract The need for higher efficiencies and performance in gas-turbine engines that propel aircraft in the air, and generate electricity on land, is pushing the operating temperatures of the engines to unprecedented levels. Replacing some of the current hot-section metallic components with ceramic-matrix composites (CMCs) is making that possible. A high-temperature ceramic coatings system, that includes environmental-barrier coatings (EBCs), are needed to protect CMCs. However, these coatings undergo degradation in the highly hostile environment of the gas-turbine engine consisting of a combination of high gas temperatures, pressures, and velocities. In addition, there is the ubiquitous presence of steam (a combustion by-product) and occasional ingestion of calcia-magnesia-aluminosilicates (CMASs) in the form of dust, sand, or ash from the environment. Steam can cause corrosion of EBCs, and the molten CMAS deposits can react with the EBCs resulting in their failure. This article provides a perspective on the understanding of these degradation mechanisms, and possible approaches, guided by that understanding, for mitigating the degradation. An outlook on the future challenges and opportunities is presented.

Padture, Nitin P. (ORCID:0000000166228559)↗
DOE OSTI2019

Multiscale experimental characterization of coatings on ceramics: A case study of tungsten on SiC

State-of-the-art transmission Kikuchi diffraction (TKD) and high-speed nano-indentation were combined with glow-discharge optical emission spectroscopy (GDOES), transmission electron microscopy (TEM) and micro-cantilever testing to characterize microstructures and mechanical properties of coatings on a ceramic substrate. The goal was to develop a multiscale experimental characterization method to assess the coating/substrate couple. A tungsten coated silicon carbide substrate was the system used for this development. The combination of GDOES, TEM and TKD enabled precise phase identification in the system, while TKD provided superior spatial resolution for phase identification. Here micro-cantilever tests were able to measure adhesion strength, with support from high-speed nano-indentation which enabled rapid modulus and hardness determination over relatively large areas.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Interfacial Characteristics Investigation for One-Step EDM Drilling of Cooling Holes in TBCs

In this study, the one-step electrical discharge machining of inclined cooling holes is performed in thermal-barrier-coated nickel-based superalloys via the assisting electrode method. The effects of the process parameters, including the inclination angle, peak current, pulse duration, and duty cycle, on interfacial characteristics of cooling holes were investigated. The research results are as follows: After machining, the hardness of TBCs increases slightly and the adhesion strength of ceramic coating has a slight reduction. Delamination prevailingly appears at the ceramic coating/bonding coating interface, and its length at the trailing edge is greater than that at the leading edge. Increasing either the discharge energy or the duty cycle also aggravates the severity of the delamination. Under an excessive peak current of 22.5 A, the complete spalling of the ceramic coating occurs in the vicinity of the holes. Additionally, a reduction in the inclination angle results in a significant increase in delamination cracking and poorer interface integrity. The interfacial microstructure features of the holes vary with the inclination angle. The large-scale spalling of ceramic coating is prone to occur at the trailing edge when using an inclination angle of 30°. The spattering is susceptible to appear at the entrance of the holes under inclination angles of 60° and 75°, and its composition is primarily Ni, C, Zr, Cr, Nb, Fe, and Cu.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Al 2 O 3 /TiO 2 coated separators: Roll-to-roll processing and implications for improved battery safety and performance

Heat generation is one of the major concerns with lithium-ion batteries (LIB) while charging them at higher currents, which could inadvertently impact the rate performance and reduce the safety of the cell. Polymer separator is one of the least thermal conductive components of a LIB. In addition, commercial separators for LIB are made from polyolefin membranes that tend to shrink and curl at higher temperatures due to their lower melting temperature (~130 °C). Developing separators with improved thermal stability and higher electrolyte uptake is essential for enhancing the safety as well as the performance of the LIB. In this work, a thin layer of ceramic coatings (Al 2 O 3 and TiO 2 ) is applied on propylene (PP) membrane to improve the thermal stability and electrolyte affinity without compromising the rate performance. A slurry with 100% Al 2 O 3 coated on the polypropylene separator exhibited the best improvement in thermal stability ( shrinkage of 0.6% vs 6.0% for uncoated membrane) and excellent rate performance with 92% capacity retention at 2C. The Al 2 O 3 coated separator demonstrated excellent electrolyte wettability compared to the uncoated membrane. The cross-plane thermal conductivity of the ceramic coated separators is analyzed to understand their heat transfer behavior. The thermal conductivity of the separator is improved by ~3.2 times with the Al 2 O 3 coating.

25 ENERGY STORAGE↗
DOE OSTI2024

One-Pot Coating of Ceramic Powders by Exfoliated Boron Nitride Layers with a Dense CO 2 Medium and Ultrasound-Aided Mixing

The coating or doping of substrates by two-dimensional materials to impart superior functional properties (such as improved thermal conductivity, bacterial resistance, reduced friction) is receiving increased attention. Environmentally benign, rapid and scalable coating techniques are desirable for this purpose. Here, we report a novel process for coating alumina, silicon carbide and boron carbide substrates with hexagonal boron nitride (h-BN) layers. The process consists of two sequential steps. First, h-BN layers are exfoliated from bulk h-BN in supercritical carbon dioxide (scCO 2 ) using ultrasound-aided mixing. This step is followed by self-assembly (i.e., coating) of the exfoliated h-BN on the substrates in liquid CO 2 also aided by ultrasound. The liquid CO 2 state is achieved by simply lowering the pressure and temperature of the first step below the critical point of CO 2 (P c = 72.8 atm; T c = 31.1 °C). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) micrographs clearly reveal the exfoliation of h-BN under scCO 2 conditions as well as the h-BN assembly on various substrates under liquid CO 2 conditions. X-ray diffraction patterns confirm the structural integrity of the coated h-BN layers. It was also confirmed that without a transition to the liquid CO 2 phase following exfoliation in scCO 2 , there was negligible coating of h-BN on the substrates. Researchers in the field could consider this benign process to rapidly coat or dope materials with h-BN and other 2D materials to impart improved functional properties in myriad applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Preliminary Design and Testing of Candidate Coating Materials Applied to Inconel Bubblers for Improved Corrosion Resistance

The US Department of Energy (DOE) Office of Environmental Management Technology Development (EM-TD) has requested Savannah River National Laboratory (SRNL) evaluate ceramic coating materials that can extend the service life of Hanford melter bubblers. The proposed Task will focus on the development of ceramic coating materials for Inconel bubblers to reduce corrosion and increase the service life of the bubblers.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Thermal Analysis and Simulations of the Abort Kicker Magnets Systems for the Electron-Ion Collider

The Abort Kicker Magnets system used in the current Relativistic Heavy Ion Collider (RHIC) to steer the circulating beam into the dump will be subjected to higher heat loads in the Electron-Ion Collider (EIC). After analyzing the existing abort kicker magnets and running thermal simulations in ANSYS it was concluded that they may not be suitable for use as-is in the future EIC due to heat and impedance concerns in the magnets. Possible solutions include adding a round titanium-coated ceramic beam tube to help solve the heat and impedance concerns, but this will reduce the limiting aperture of the kicker magnet. Another possible solution to meet all the performance requirements for EIC would be to add titanium-coated ceramic plates with water-cooling and tapered transitions that significantly improve the impedance and lower the heat in the magnets with less reduction to the aperture.

43 PARTICLE ACCELERATORS↗