Search NASA⌕ Search

SEARCH · Search NASA

Results for “yttria stabilized”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Impact of Sr-Containing Secondary Phases on Oxide Conductivity in Solid-Oxide Electrolyzer Cells

Solid-oxide electrolyzer cells (SOECs) based on a yttria-stabilized zirconia (YSZ) oxide electrolyte produce hydrogen from water with the assistance of excess thermal energy; however, Sr diffusion within the Gd-doped CeO 2 (GDC) barrier layer during processing or operation can lead to the formation of unwanted secondary phases such as SrO and SrZrO 3 . Here, to establish and compare the degree of impact of these phases on SOEC performance, we conduct first-principles calculations to study their bulk oxide conductivities and compare them to that of the YSZ electrolyte. We find that SrO has a low conductivity arising from the poor mobility and low concentration of mobile oxygen vacancies, and its presence in SOECs should therefore be avoided. SrZrO 3 also has a lower oxide conductivity than YSZ; however, this discrepancy is primarily due to lower vacancy concentrations rather than low mobility. We find that sufficient levels of Y-doping on the Zr site can increase oxygen vacancy concentrations in SrZrO 3 to achieve an oxide ionic conductivity on par with that of YSZ, thereby mitigating any potential deleterious effect on transport performance. Energy-dispersive X-ray spectroscopy confirms that Y is the most common minority element present in SrZrO 3 forming near the GDC–YSZ interface, alleviating concerns regarding the impact of SrZrO 3 on device performance. These results from our combined computational–experimental analysis can inform future engineering strategies designed to limit the detrimental effects of Sr-induced secondary phase formation on SOEC performance.

08 HYDROGEN↗
DOE OSTI2020

The Detection of Monoclinic Zirconia and Non-Uniform 3D Crystallographic Strain in a Re-Oxidized Ni-YSZ Solid Oxide Fuel Cell Anode

The solid oxide fuel cell (SOFC) anode is often composed of nickel (Ni) and yttria-stabilized zirconia (YSZ). The yttria is added in small quantities (e.g., 8 mol %) to maintain the crystallographic structure throughout the operating temperatures (e.g., room-temperature to >800 °C). The YSZ skeleton provides a constraining structural support that inhibits degradation mechanisms such as Ni agglomeration and thermal expansion miss-match between the anode and electrolyte layers. Within this structure, the Ni is deposited in the oxide form and then reduced during start-up; however, exposure to oxygen (e.g., during gasket failure) readily re-oxidizes the Ni back to NiO, impeding electrochemical performance and introducing complex structural stresses. In this work, we correlate lab-based X-ray computed tomography using zone plate focusing optics, with X-ray synchrotron diffraction computed tomography to explore the crystal structure of a partially re-oxidized Ni/NiO-YSZ electrode. These state-of-the-art techniques expose several novel findings: non-isotropic YSZ lattice distributions; the presence of monoclinic zirconia around the oxidation boundary; and metallic strain complications in the presence of variable yttria content. This work provides evidence that the reduction–oxidation processes may destabilize the YSZ structure, producing monoclinic zirconia and microscopic YSZ strain, which has implications upon the electrode’s mechanical integrity and thus lifetime of the SOFC.

25 ENERGY STORAGE↗
NASA NTRS2007

Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells

A family of glass/ceramic composite materials has been investigated for use as sealants in planar solid oxide fuel cells. These materials are modified versions of a barium calcium aluminosilicate glass developed previously for the same purpose. The composition of the glass in mole percentages is 35BaO + 15CaO + 5Al2O3 + 10B2O3 + 35SiO2. The glass seal was found to be susceptible to cracking during thermal cycling of the fuel cells. The goal in formulating the glass/ ceramic composite materials was to (1) retain the physical and chemical advantages that led to the prior selection of the barium calcium aluminosilicate glass as the sealant while (2) increasing strength and fracture toughness so as to reduce the tendency toward cracking. Each of the composite formulations consists of the glass plus either of two ceramic reinforcements in a proportion between 0 and 30 mole percent. One of the ceramic reinforcements consists of alumina platelets; the other one consists of particles of yttria-stabilized zirconia wherein the yttria content is 3 mole percent (3YSZ). In preparation for experiments, panels of the glass/ceramic composites were hot-pressed and machined into test bars.

Bansal, Narottam P.↗
DOE OSTI2022

Thermal Stability and Mechanical Properties of Cold-Sprayed Nickel-Yttria Coating

The microstructural evolution under the extreme environments imposed during cold spray deposition of cermet coatings and the microstructural recovery during post-processing annealing treatments is rather complex and not well understood. Here, Ni-Yttria cermet coatings on an SS304 substrate were produced using cold spray technique, resulting in a bimodal grain structure. The grain growth, phase stability, hardness, and wear properties are observed in as-deposited and annealed (at 400 °C) Ni-Yttria and pure Ni coatings. A multimodal microstructural characterization using electron microscopy, and atom probe tomography shows the structural and compositional stability of yttria particles and Ni grains. A fragmentation of Y-rich particles and dispersion in Ni was observed, however, no forced mixing/dissolution of Y in Ni is detected. Nano-yttria dispersed within the Ni grains slowed the grain growth during annealing. After annealing, Yttria reinforced coating was 1.5 times harder and showed better thermal and mechanical stability compared to the Ni coating.

Gwalani, Bharat↗
NASA NTRS2015

Thermal Conductivity and Erosion Durability of Composite Two-Phase Air Plasma Sprayed Thermal Barrier Coatings

To enhance efficiency of gas turbines, new thermal barrier coatings (TBCs) must be designed which improve upon the thermal stability limit of 7 wt% yttria stabilized zirconia (7YSZ), approximately 1200 C. This tenant has led to the development of new TBC materials and microstructures capable of improved high temperature performance. This study focused on increasing the erosion durability of cubic zirconia based TBCs, traditionally less durable than the metastable t' zirconia based TBCs. Composite TBC microstructures composed of a low thermal conductivity/high temperature stable cubic Low-k matrix phase and a durable t' Low-k secondary phase were deposited via APS. Monolithic coatings composed of cubic Low-k and t' Low-k were also deposited, in addition to a 7YSZ benchmark. The thermal conductivity and erosion durability were then measured and it was found that both of the Low-k materials have significantly reduced thermal conductivities, with monolithic t' Low-k and cubic Low-k improving upon 7YSZ by approximately 13 and approximately 25%, respectively. The 40 wt% t' Low-k composite (40 wt% t' Low-k - 60 wt% cubic Low-k) showed a approximately 22% reduction in thermal conductivity over 7YSZ, indicating even at high levels, the t' Low-k secondary phase had a minimal impact on thermal in the composite coating. It was observed that a mere 20 wt% t' Low-k phase addition can reduce the erosion of a cubic Low-k matrix phase composite coating by over 37%. Various mixing rules were then investigated to assess this non-linear composite behavior and suggestions were made to further improve erosion durability.

Rare earth zirconia↗
NASA NTRSDate not supplied

Enhanced Thermal Stability of High Yttria Concentration YSZ Aerogels

Aerogels demonstrate extraordinarily low thermal conductivity and low density, presenting a promising form of lightweight insulation for aerospace applications. The primary challenge is stabilization of the highly porous structure at temperatures to 1200 °C. Upon collapse of the pore structure, the favorable thermal properties and low density are diminished. Yttria-stabilized zirconia (YSZ) aerogels are synthesized to investigate the effect of composition on morphology, phase behavior, and thermal stability (specific surface area, pore size distribution). This work demonstrates the improvement in thermal stability of zirconia aerogels with increased yttria content. Furthermore, changes in structure and surface chemistry of YSZ aerogels are studied in both oxidizing and inert atmospheres. With an improved understanding of aerogel structure and performance, metal oxide aerogels can be developed to withstand the extreme environments of space exploration.

Nathaniel Olson↗
NASA NTRS2020

Durability of YSZ coated Ti2AlC in 1300°C high velocity burner rig tests

A thermal barrier coating system survived 500 h in cyclic burner rig tests at 1300°C, exceeding the life of all previous systems. An yttria stabilized zirconia (7YSZ) thermal barrier coating (TBC) was plasma sprayed on the oxidation resistant Ti2AlC MAX phase and tested in a jet fuel burner. No coating spallation or recession was observed, only a 2.4 mg/sq.cm mass gain due to typical cubic Al2O3 oxidation kinetics. The modest weight gain contrasted with large TBC spallation or oxide volatility losses that might occur under cyclic, high velocity (~100 m/s) burner conditions. The coating surface exhibited colonies of [111]flourite fiber-textured columns separated by craze crack patterns, but with no visible moisture attack. The thickness of the alumina scale under the YSZ face was >20 μm, more than twice that formed on TBC/superalloy systems at failure. TiO2 nodules, initially formed on the uncoated backside, were then removed as volatile hydroxides formed in high temperature, high velocity water vapor (~10%). Overall, the test indicated the exceptional stability of the YSZ/Ti2AlC system under turbine conditions, due in large part to good thermal expansion matching.

alumina, MAX phases, thermal barrier coatings (TBC↗
DOE OSTI2020

Quantifying thermal barrier coating delamination through luminescence modeling

Thermal barrier coatings (TBCs) are widely used in the hot sections of gas turbine systems as they are remarkably efficient in insulating the underlying superalloys, leading to higher operating temperatures and therefore enhancing the performance of the engines. However, this benefit is only possible if the integrity of the TBC under aggressive thermo-mechanical environments is ensured. Delamination is a common but hard to detect failure mode. We present, in this work, supported by experimentation, the implementation of a modeling approach applying the Kubelka-Munk theory to provide numerical quantification of luminescence contrast and intensity due to top coat delamination in TBCs. The method relies on the drastic change in reflectivity when a delamination forms, exploiting it for high-contrast luminescence mapping. Two distinct TBC configurations containing an erbium-doped yttria-stabilized zirconia (YSZ:Er 3+ ) layer for delamination sensing were used to validate this model. A delamination zone induced by Rockwell indentation was successfully tracked by measuring an increase of the intensity of the erbium emission line at 562 nm. Luminescence-based methods for delamination detection can provide a revolutionary non-invasive technique, with potential for both off-line and on-line engine monitoring.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Solid-State Sintering of Core-Shell Ceramic Powders Fabricated by Particle Atomic Layer Deposition

The properties of technical ceramics are highly dependent on their microstructure, which evolves during sintering. Sintering is the process by which ceramic parts are subjected to high temperatures to activate chemical diffusion and the consumption of porosity. During the initial stage of sintering, interparticle necks between neighboring particles form and subsequently increase in size, consuming porosity as the particle centers move closer together. To experimentally determine how this process depends on particle surface composition, particle atomic layer deposition (ALD) was used to deposit a thin film of amorphous aluminum oxide (Al2O3) onto yttria-stabilized tetragonal zirconia (3YSZ) particles, producing core-shell structured powders. The uniformity of the Al2O3 film was confirmed with transmission electron microscopy and energy dispersive spectroscopy. Scanning electron microscopy was used to observe microstructural evolution during sintering, and the dihedral angles of Al2O3 and 3YSZ grains were measured to determine the ratio of interfacial energies between the 3YSZ|3YSZ, 3YSZ|Al2O3, and Al2O3|Al2O3 interfaces. Analysis of the densification kinetics revealed that the initial stage of densification is dependent on the material at the surface of the particles (ie, the Al2O3 film) and is controlled by the diffusion of Al3+ cations through Al2O3. Once the Al2O3 film has coalesced, the sintering behavior is controlled by the densification of the core material (3YSZ). Thus, core-shell powders fabricated by particle ALD sinter by a two-step process where the kinetics are dependent on the material present at interparticle contacts.

alumina↗
DOE OSTI2021

Polysiloxane coatings on microspheres based on Multiphase Flow with Interface Exchange-Discrete Element Modelling

Polysiloxane coatings on yttria stabilized zirconia (YSZ) microspheres of 500 μm were simulated in a spout fluidized bed coater using Multiphase Flow with Interface Exchange-Discrete Element Modelling (MFiX-DEM). In this work, two different coater configurations were developed to study the influence of gas velocity and its distribution on particle dynamics. The presence of the Wurster tube not only enhances the distribution but also increases the overall residence time of the particles. Investigations were also carried out with different Wurster tube positions (normal, 10% and 20% lowered from its initial position). Among these, 20% lowered Wurster tube position demonstrated the most effective coating process. The effects of gas inlet pressure on the average gas velocity and the distribution of particles were analyzed. More than 97% of the particles can be retained. The derived results, including average gas velocity, particle retention percentage, and distribution of particles with gas velocity, are being used to guide the experimental work in obtaining defect-free coatings for YSZ microspheres.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Comparative analysis of temperature dependent properties of commercial nuclear fuel pellet and surrogates undergoing cracking: A review

A variety of normal and accident scenarios can generate thermal stresses enough to cause cracking in light water reactor (LWR) fuel. To better understand this behavior, cracking experiments have been carried out to induce thermal gradients in fuel pellets via induction heating and direct resistance heating. In this study, Ceria (CeO 2 ) and yttria stabilized zirconia (YSZ) pellets were chosen as a surrogate fuel material for uranium dioxide (UO 2 ). Induction heating was done using copper coils and molybdenum susceptors which heated the surrogates to a threshold temperature that is sufficiently high for the fuel material to conduct current. Thereafter, direct resistance heating was achieved by passing current through the specimen using a DC power supply to introduce volumetric heating to replicate reactor operating conditions. Simultaneous real-time dual imaging of the ceria pellet surface has been designed using optical and infra-red camera system to capture images of cracks and full-field temperature gradients on pellet. It was observed that YSZ pellets need a much higher voltage-current for volumetric heating and do not exhibit the cracking pattern as ceria and UO 2 , hence YSZ was ruled out for further consideration. Ceria was found to be an appropriate surrogate for UO 2 . Furthermore, the experimental set up and test conditions demand the need to primarily understand the thermo-physical, mechanical and optical properties of UO 2 and the surrogates. Thus, it is essential to have an in-depth knowledge about the various temperature dependent properties of UO 2 and CeO 2 for establishing a comparative analysis between the surrogate and UO 2 for conducting experiments.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Multilayer ceramic oxide solid electrolyte for fuel cells and electrolysis cells

A unitary layered ceramic structure is disclosed which comprises co-sintered layers. The co-sintered structure comprises a sintered central layer of yttria stabilized zirconia (YSZ) which is about 8 mole percent yttria and having a density of at least about 95% of theoretical, and sintered outer layers of strontium lanthanum manganite (LSM) having the approximate molecular composition La.sub.0.8 Sr.sub.0.2 MnO.sub.3, having a density from about 50 to about 60% of theoretical, and having interconnected porosity from about 40 to 50% with an interconnected pore diameter from about one micron to about five microns. The sintered central layer is sandwiched by and bonded and sintered to the outer layers and is essentially free of significant amounts of manganese. A process for making the unitary composition-of-matter is also disclosed which involves tape casting a LSM tape and then on top thereof casting a YSZ tape. The process comprises presintering LSM powder at 1250.degree. F., crushing the presintered commercially available LSM powder, forming a slurry with the crushed LSM, a binder and solvent, tape casting the slurry and allowing the slurry to air dry. A mixture of commercially available submicron size particle YSZ powder is milled with a dispersant and solvent to disperse the YSZ particles thereby forming a dispersed YSZ slurry. The YSZ slurry is then tape cast on the dried LSM tape. If desired, a third layer of LSM can be cast on top of the dried YSZ layer. After drying the composite LSM/YSZ and LSM/YSZ/LSM tapes are fired at 1300.degree. C. No migration of manganese into the YSZ layer was observed with scanning electron microscope/edax in the sintered multilayer tape.

Schroeder, James E.↗
NASA NTRS1990

Multilayer ceramic oxide solid electrolyte for fuel cells and electrolysis cells and method for fabrication thereof

An unitary layered ceramic structure is disclosed which comprises co-sintered layers. The co-sintered structure comprises a sintered central layer of yttria stabilized zirconia (YSZ) which is about 8 mole percent yttria and having a density of at least about 95% of theoretical, and sintered outer layers of strontium lanthanum manganite (LSM) having the approximate molecular composition La.sub.0.8 Sr.sub.0.2 MnO.sub.3, having a density from about 50 to about 60% of theoretical, and having interconnected porosity from about 40 to 50% with an interconnected pore diameter from about one micron to about five microns. The sintered central layer is sandwiched by and bonded and sintered to the outer layers and is essentially free of significant amounts of manganese. A process for making the unitary composition-of-matter is also disclosed which involves tape casting a LSM tape and then on top thereof casting a YSZ tape. The process comprises presintering LSM powder at 1250.degree. F., crushing the presintered commercially available LSM powder, forming a slurry with the crushed LSM, a binder and solvent, tape casting the slurry and allowing the slurry to air dry. A mixture of commercially available submicron size particle YSZ powder is milled with a dispersant and solvent to disperse the YSZ particles thereby forming a dispersed YSZ slurry. The YSZ slurry is then tape cast on the dried LSM tape. If desired, a third layer of LSM can be cast on top of the dried YSZ layer. After drying the composite LSM/YSZ and LSM/YSZ/LSM tapes are fired at 1300.degree. C. No migration of manganese into the YSZ layer was observed with scanning electron microscope/edax in the sintered multilayer tape.

Schroeder, James E.↗
DOE OSTI2021

Generation of electric-field stabilized zirconium monoxide secondary phase within cubic zirconia

Flash sintering of cubic yttria-stabilized zirconia has been studied via in situ energy dispersive diffraction. A secondary rocksalt-phase zirconium monoxide was observed emerging from the primary fluorite-phase zirconium dioxide, previously only observed as a thin interlayer at metal-oxide interfaces, upon application of a direct current electric field. The average secondary phase intensity rose over extended flow of direct current through the ceramic, faded upon removal of the field and disappeared entirely upon application of an alternating current electric field. The results indicate that the sustained application of a direct current electric field can result in significant electrochemical reduction of zirconia under high current density conditions. Poor sinterability and cracking under direct current is apparent and potential mechanisms discussed therein.

36 MATERIALS SCIENCE↗
NASA NTRS1985

Advanced thermal barrier coating systems

Current state-of-the-art thermal barrier coating (TBC) systems consist of partially stabilized zirconia coatings plasma sprayed over a MCrAlY bond coat. Although these systems have excellent thermal shock properties, they have shown themselves to be deficient for a number of diesel and aircraft applications. Two ternary ceramic plasma coatings are discussed with respect to their possible use in TBC systems. Zirconia-ceria-yttria (ZCY) coatings were developed with low thermal conductivities, good thermal shock resistance and improved resistance to vanadium containing environments, when compared to the baseline yttria stabilized zirconia (YSZ) coatings. In addition, dense zirconia-titania-yttria (ZTY) coatings were developed with particle erosion resistance exceeding conventional stabilized zirconia coatings. Both coatings were evaluated in conjunction with a NiCr-Al-Co-Y2O3 bond coat. Also, multilayer or hybrid coatings consisting of the bond coat with subsequent coatings of zirconia-ceria-yttria and zirconia-titania-yttria were evaluated. These coatings combine the enhanced performance characteristics of ZCY with the improved erosion resistance of ZTY coatings. Improvement in the erosion resistance of the TBC system should result in a more consistent delta T gradient during service. Economically, this may also translate into increased component life simply because the coating lasts longer.

Dorfman, M. R.↗
NASA NTRS1978

Effects of compositional changes on the performance of a thermal barrier coating system

Currently proposed thermal barrier systems for aircraft gas turbine engines consist of NiCrAlY bond coating covered with an insulating oxide layer of yttria-stabilized zirconia. The effect of yttrium concentration (from 0.15 to 1.08 w/o) in the bond coating and the yttria concentration (4 to 24.4 w/o) in the oxide layer were evaluated. Furnace, natural gas-oxygen torch, and Mach 1.0 burner rig cyclic tests on solid specimens and air-cooled blades were used to identify trends in coating behavior. Results indicate that the combinations of yttrium levels between 0.15 - 0.35 w/o in the bond coating and the yttria concentration between 6 - 8 w/o in the zirconium oxide layer were the most adherent and resistant to high temperature cyclic exposure.

Stecura, S.↗
DOE OSTI2020

Integrated Harsh Environment Gas / Temperature Wireless Microwave Acoustic Sensor System for Fossil Energy Applications

There is a significant need for sensors capable of detecting gases, such as H 2 , O 2 , NO x , SO x within harsh environments encountered in power plants, industrial manufacturing, oil and gas exploration, and aerospace applications. This project successfully demonstrated the use of wireless microwave acoustic sensor technology for the detection of gases (H 2 or O 2 ) from ambient temperatures up to 650°C. The work focused on langasite (LGS) based surface acoustic wave resonator (SAWR) sensors as the harsh-environment sensor platform and explored multiple combinations of high-temperature thin films and device structures which were used to increase the sensor platform stability and detection capability at temperatures in the operational range of 150°C to 700°C. Specific material configurations that were investigated include: yttria-stabilized-zirconia (YSZ) decorated with Pt nanoparticles, atomic layer deposited (ALD) Al 2 O 3 , palladium, and Pt/Al 2 O 3 co-deposited electrode alloys. Through the deposition of YSZ at temperatures as high as 850°C and the use of graded alloy concentrations of Pt in the fabrication of the Pt/Al 2 O 3 electrode structures, film stress problems were mitigated, and sensor operation and stability achieved. To test and evaluate SAWR sensor performance for the detection of H 2 and O 2 under the influence of temperature variations, a comprehensive gas sensor control system and test apparatus was created to operate within a laboratory box furnace-controlled environment. In addition to the advancement in thin film materials through the deposition and fabrication techniques mentioned above, the work characterized the performance of sensors containing these films in the presence of oxidizing and reducing gases between 25°C and 700°C. In particular, the work revealed that the exposure of the SAWR sensor surfaces to oxidizing environments significantly improve the sensor response to H 2 , whereas the exposure of the sensor to reducing environments at high temperatures (≈ 500°C) renders the sensor irresponsive to H 2 , requiring sensor surface treatment at high temperatures (above 500°C) to recover the responsiveness to H 2 . The SAWR sensors have been also tested for wireless operation and array operation using multiple orientations to resolve the detection of gases under temperature variations. The work developed at the University of Maine was aided by a collaboration with the NETL Research and Innovation Center, Pittsburgh, PA, where thin film materials and device structures fabricated at UMaine were tested and characterized using NETL gas reactors and surface analysis techniques. SAWR sensors fabricated at UMaine were exposed multiple times to temperatures up to 700°C and H 2 concentrations up to 100% in the NETL facilities to measure the sensor performance. Environetix Technologies Corporation, a UMaine harsh-environment sensor spin-off company, also provided support and assistance in sensor system testing and implementation. The sensor small size and configuration allows flexible sensor placement and embedding of multiple sensor arrays into a variety of components within power systems and other aerospace or industrial settings that need to be interrogated wirelessly. The SAW platform is an attractive option for high-temperature harsh-environment gas sensing applications due to its inherent features, namely small size, capability of battery-free and wireless operation, and cost effective scale production using well-established production techniques from the semiconductor industry. The research findings achieved in this work, particularly advances regarding the fabrication and performance of the SAWR gas sensor platform, can be adapted and transferred to industrial power plants and other harsh environments.

01 COAL, LIGNITE, AND PEAT↗
NASA NTRSDate not supplied

Optimization of Aerogels for High Temperature Applications

Aerogels can be used in spaceflight applications as thermal insulators due to their low density, low thermal conductivity, and tortuous path for solid conduction. However, the aerogel formulation must be optimized to increase the thermal stability of the aerogels as drastic densification and decrease in surface area is often exhibited after high-temperature exposure. Current research investigates yttria-stabilized zirconia (YSZ) aerogels, which have low thermal conductivity and are expected to be used between 600°C and 1000°C. We anticipate that new sol-gel chemistries and processing will yield YSZ aerogels that display retained mesoporous structure, increased surface area, and minimized shrinkage upon exposure to higher temperatures in the projected use range. This work investigates the cationic surfactant, cetrimonium bromide (CTAB), as a templating agent to prevent the collapse of the aerogel pore structure upon gelation and drying. It was determined that adding one-half times the critical micelle concentration (CMC) of CTAB increased the surface area and pore volume of the aerogels, as compared to aerogels without CTAB or with twice the CMC of CTAB, following high-temperature exposure. By optimizing CTAB, the thermal stability of YSZ aerogels can be enhanced to make these materials more efficient when used as thermal management systems.

Rebecca C Walker↗