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Results for “adherence to substrate”

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 OSTI2025

Sputter deposition of ultrathick Bi coatings onto rotating substrates for inertial confinement fusion

Sputter-deposited Bi is a potential candidate material for the production of inertial confinement fusion (ICF) hohlraums, which are sphero-cylindrical canisters that serve as the housing for hydrogen-fuel-filled capsules in ICF implosions. The fabrication of hohlraums involves deposition onto rotating sphero-cylindrical substrates and, hence, requires an understanding of oblique angle deposition phenomena. Here, we systematically study the effect of dynamic substrate tilt on properties of Bi films deposited onto rotating planar substrates. Results show that film morphology, porosity, and electrical resistivity depend on substrate tilt. In comparison with films deposited onto substrates adhered to a stationary sample holder, films deposited on rotating substrates have more uniform microstructure with fewer void defects. Based on Monte Carlo simulations, these changes in film morphology and microstructure are attributed to averaging and geometric effects related to sample position and rotation. In conclusion, the fabrication of an ∼ 50-µm-thick Bi film on a rotating sphero-cylindrical mandrel demonstrates a significant step toward the production of Bi hohlraums.

Bismuth↗
DOE OSTI2021

Adsorption cooling system using carbon aerogel

A highly adsorptive structure includes: a substrate; and a carbon aerogel adhered to the substrate, wherein the carbon aerogel is characterized by having physical characteristics of in-situ formation on the substrate, and wherein the carbon aerogel is configured to selectively adsorb and desorb one or more refrigerants selected from the group consisting of: acid halides, alcohols, aldehydes, amines, chlorofluorocarbons, esters, ethers, fluorocarbons, perfluorocarbons, halocarbons, halogenated aldehydes, halogenated amines, halogenated hydrocarbons, halomethanes, hydrocarbons, hydrochlorofluorocarbons, hydrofluoroethers, hydrofluoroolefins, inorganic gases, ketones, nitrocarbon compounds, noble gases, organochlorine compounds, organofluorine compounds, organophosphorous compounds, organosilicon compounds, oxide gases, refrigerant blends and thiols.

Baumann, Theodore F.↗
DOE OSTI2021

Adsorption cooling system using carbon aerogel

An adsorptive cooling system includes: a first highly adsorptive structure positioned to receive thermal energy from a thermal energy source, the first highly adsorptive structure including: a first substrate; and a first carbon aerogel adhered to the first substrate, a second highly adsorptive structure positioned to receive thermal energy from the thermal energy source, the second highly adsorptive structure including: a second substrate; and a second carbon aerogel adhered to the second substrate, a cooling unit; and a circulation system adapted for circulating the refrigerant from at least one of the first highly adsorptive structure and the second highly adsorptive structure to the cooling unit to provide cooling from the thermal energy source and to return the refrigerant from the cooling unit to at least one of the first highly adsorptive structure and the second highly adsorptive structure.

Baumann, Theodore F.↗
DOE OSTI2021

The effect of substrate temperature on the critical velocity in microparticle impact bonding

A number of nascent coating and micromanufacturing processes involve particles sprayed at a high velocity, which impact a substrate, deform, and adhere. Successful bonding between the particles and the substrate requires impact velocities higher than the so-called critical adhesion velocity. This critical velocity is influenced by the temperature of the substrate, a variable that we isolate in this work by conducting single-particle impacts on a variable-temperature substrate for three systems (Al–Al, Sn–Sn, and Ti–Ti) with particles individually selected within a narrow size distribution. Our results quantitatively connect the increase in substrate temperature to a significant lowering of the critical velocity, which we attribute to the lower dynamic strength of the thermally softened substrate. The data are generally consistent with expectations for bonding being controlled by a hydrodynamic process of jetting upon impact.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Membrane electrode assembly manufacturing process

Methods and compositions for making fuel cell components are described. In one embodiment, the method comprises providing a substrate, and forming or adhering an electrode on the substrate, wherein the forming includes depositing an aqueous mixture comprising water, a water-insoluble component, a catalyst, and an ionomer. The water-insoluble component comprises a water-insoluble alcohol, a water-insoluble carboxylic acid, or a combination thereof. The use of such water-insoluble components results in a stable liquid medium with reduced reticulation upon drying, reduced dissolution of the substrate, and reduced penetration of the pores of the substrate.

Edmundson, Mark↗
DOE OSTI2022

System for providing dynamic feedback for selective adhesion PCB production

A system for providing selective adhesion printed circuit board (PCB) production comprises a conveyor mechanism, a curing system, and a computer. The conveyor mechanism is configured to convey a series of selective adhesion blanks, wherein each selective adhesion blank is utilized to produce a PCB and includes a flexible film, a substrate, a conductive layer, and a curable adhesive. The conductive layer is formed from electrically conductive material and adhered to the substrate. The curable adhesive is positioned between the flexible film and the conductive layer and is configured to selectively bond with the conductive layer when the curable adhesive is cured. The curing system is configured to cure the curable adhesive. The computer includes a processing element configured or programmed to: receive a plurality of PCB designs, and direct the curing system to cure the curable adhesive of a plurality of selective adhesion blanks for each PCB design.

Hatch, Jonathan Douglas↗
DOE OSTI2023

Effect of an oxide layer on high velocity impact of tantalum particles characterized using molecular dynamics

Micro-cold spray, also commonly referred to as the aerosol deposition method or vacuum kinetic spraying, is a process for depositing nanostructured films of metals and ceramics by impacting solid nanoparticles at high velocity onto a substrate at room temperature and at low pressures. Tantalum films deposited by micro-cold spray are desirable because tantalum is non-reactive to certain molten metals and can therefore serve as a non-reactive barrier coating. However, unlike most other metals deposited by micro-cold spray, tantalum quickly forms an oxide layer when exposed to air. In the deposition of films using traditional cold spray with much larger particles, native oxides must fracture for particle–substrate bonding to occur. Furthermore, the fraction of the particle that is oxidized in micro-cold spray and the strain rates experienced by the particles upon impact are both much larger than in cold spray, suggesting that the role of the oxide on film deposition may be distinct. The effect of this oxide layer on particle deformation and adherence to a substrate under high strain rates is studied using molecular dynamics simulations. The effect of oxide layer thickness, particle diameter, and impact velocity are examined.

42 ENGINEERING↗
DOE OSTI2021

Enhanced oxidation resistance of (Mo 95 W 5 ) 85 Ta 10 (TiZr) 5 refractory multi-principal element alloy up to 1300°C

Refractory-metal-based alloys are a potential replacement of current nickel-based superalloys due to their excellent mechanical strength at extremely high temperatures. However, severe oxidation in a high-temperature working environment limits their application. To address this challenge, a two-step coating process (including a Mo precoat and a Si-B pack cementation) was applied to an innovative refractory multi-principal element alloy (RMPEA) (Mo 95 W 5 ) 85 Ta 10 (TiZr) 5 . The coating is composed of an aluminoborosilica glass layer on top of a RMPEA-Si-B multilayered structure. Here, the coating effectively protects the RMPEA from oxidation in high-temperature environments, as demonstrated by phase-stable operation at 10–20% higher temperatures over state-of-the-art systems without any forced-cooling system. Following an isothermal exposure at 1300 °C, the weight change of the coated sample follows a paralinear kinetics with a minor weight loss of 4.2 mg/cm 2 after 50 h. Thermal cycling tests between 1300 °C and room temperature in air resulted in the total weight gain of only 2.6 mg/cm 2 after 450 cycles. The coating shows an excellent adherence to the substrate with a boride layer acting as a barrier that maintains the coating integrity. This two-step Mo-Si-B coating method can be adapted to provide environmental resistance to a wide range of RMPEA.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Superhydrophobic coating and process of making same

An improved superhydrophobic coating and a process of making it is provided herein. More particularly, a robust superhydrophobic coating is produced by using carbon dioxide to enhance the integration of a binder material into the superhydrophobic coating. The carbon dioxide may be used to infiltrate and fill the interstitial voids of a superhydrophobic material, such as diatomaceous earth. Consequently, occupying these voids in the superhydrophobic material effectively blocks other components (e.g., binders) from entering the voids. As a result, the coating formulations of the present invention are more robust and may strongly adhere to the substrates to which they are applied.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Printing transferable components using microstructured elastomeric surfaces with pressure modulated reversible adhesion

In a method of printing a transferable component, a stamp including an elastomeric post having three-dimensional relief features protruding from a surface thereof is pressed against a component on a donor substrate with a first pressure that is sufficient to mechanically deform the relief features and a region of the post between the relief features to contact the component over a first contact area. The stamp is retracted from the donor substrate such that the component is adhered to the stamp. The stamp including the component adhered thereto is pressed against a receiving substrate with a second pressure that is less than the first pressure to contact the component over a second contact area that is smaller than the first contact area. The stamp is then retracted from the receiving substrate to delaminate the component from the stamp and print the component onto the receiving substrate. Related apparatus and stamps are also discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Are Contact Angle Measurements Useful for Oxide-Coated Liquid Metals?

This work establishes that static contact angles for gallium-based liquid metals have no utility despite the continued and common use of such angles in the literature. In the presence of oxygen, these metals rapidly form a thin (~1–3 nm) surface oxide “skin” that adheres to many surfaces and mechanically impedes its flow. This property is problematic for contact angle measurements, which presume the ability of liquids to flow freely to adopt shapes that minimize the interfacial energy. We show here that advancing angles for a metal are always high (>140°)—even on substrates to which it adheres—because the solid native oxide must rupture in tension to advance the contact line. The advancing angle for the metal depends subtly on the substrate surface chemistry but does not vary strongly with hydrophobicity of the substrate. During receding measurements, the metal droplet initially sags as the liquid withdraws from the “sac” formed by the skin and thus the contact area with the substrate initially increases despite its volumetric recession. Furthermore, the oxide pins at the perimeter of the deflated “sac” on all the surfaces are tested, except for certain rough surfaces. With additional withdrawal of the liquid metal, the pinned angle gets smaller until eventually the oxide “sac” collapses. Thus, static contact angles can be manipulated mechanically from 0° to >140° due to hysteresis and are therefore uninformative. We also provide recommendations and best practices for wetting experiments, which may find use in applications that use these alloys such as soft electronics, composites, and microfluidics.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Adhesion and tribological characteristics of modified polyurethane coating on composite substrate

In the present study, glass-epoxy composites were used as a substrate to study the performance of modified polyurethane coating. Two-layer coating (180–200 µm) wherein the epoxy primer as the first coat and polyurethane as the top coat was applied using an air-assisted spray gun to increase the service life of the composite. The analysis of coating was performed using gloss, contact angle, FTIR, TGA, tensile test and SEM. The bonding strength between coating and substrate was evaluated by cross-hatch cut, 180 deg peel strength and pull-off adhesion tests. Scratch, Taber abrasion and Pin-on-disc tests were also performed to evaluate the wear resistance. In addition, a rain erosion test was performed to check the stability of the coating. From the above tests, it is concluded that the applied coating well adhered to the composite substrate. The data generated from different tests can be used to estimate the service life of polymer composites and coatings.

Mushtaq, Mohammed↗
DOE OSTI2021

Mechanical Behavior of Hybrids with Hyper-Connected Molecular Networks

Our research is focused on fundamental studies related to the molecular design, synthesis, characterization and modeling of molecular-reinforced hybrid glass films for superior mechanical and fracture properties. Molecular-reinforced hybrid glass films exhibit unique electro-optical properties while maintaining excellent thermal stability. They have important technological application for emerging nanoscience and energy technologies including anti-reflective and ultra-barrier layers in photovoltaics, display technologies, as well as quantum technologies. However, they are often inherently brittle in nature, do not adhere well to adjacent substrates, and exhibit poor mechanical properties. Furthermore, a robust understanding of the underlying mechanisms of deformation, fracture and fatigue has been lacking particularly given their mechanically fragile nature. The related lack of structure-property relationships between molecular structure, mechanical properties and processing represents a fundamental challenge to their integration into device technologies, compromises their thermomechanical reliability and has thwarted efforts to improve mechanical and, particularly, fracture properties.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Versatile coating with multifunctional performance for solar steam generation

In this work, a new kind of material, composite complex coating (CCC), with multifunctional performance has been developed for solar steam generation. The CCC has many advantages: (a) Scalability. The fabrication process is facile and mild; it can be realized in aqueous solution at room temperature, without high pressure, toxic organic solvents, or complex equipment. (b) Cost-effectiveness. The reagents used for preparation of CCC are low-cost and readily available. (c) Universality and stability. CCC firmly adheres on surfaces of various substrates with diverse shapes (cotton, filter paper, wood, polyurethane sponge, and even chemically inert and highly hydrophobic polyvinylidene fluoride membranes), and can withstand rinsing treatment (3000 r/min for 96 h), cyclic frost-thaw test (-18 °C ⇌ 30 °C, 90 times), and both high and low pH environments. In addition, many other reported coatings, such as carbon black, fail under similar process strain. (d) Anti-crude oil-fouling property. The CCC possesses stable superhydrophilicity and underwater superoleophobicity, which collectively endow substrates with the ability to resist fouling by oils. (e) Broad and strong light absorption. CCC can transform various substrates with diverse shapes into black materials with broadband light absorption due to its d-d transitions and rough surface. Together, these properties of CCC enable substrates with nearly any structural design to be easily transformed into photothermal materials for efficient solar steam generation. Furthermore, as a proof of concept, poplar wood is treated with CCC, achieving a water evaporation rate of ~1.8 kg m-2 h-1 (one sun), which is a record among wood-based photothermal materials.

14 SOLAR ENERGY↗
DOE OSTI2020

Circuit board and method of forming same

A circuit board comprising a substrate and a circuit trace. The substrate includes a surface etched via ion milling over a circuit area such that the surface has an increased roughness. The circuit trace forms portions of an electronic circuit and may be created from a thin conductive film deposited on the surface within the circuit area. The circuit trace adheres more strongly to the roughened substrate surface, which prevents the circuit trace from peeling or becoming delaminated from the substrate surface.

36 MATERIALS SCIENCE↗
DOE OSTI2020

The Transition From Rebound to Bonding in High-Velocity Metallic Microparticle Impacts: Jetting-Associated Power-Law Divergence

A metallic microparticle impacting a metallic substrate with sufficiently high velocity will adhere, assisted by the emergence of jetting—the splash-like extrusion of solid matter at the periphery of the impact. In this work, we compare real-time observations of high-velocity single-microparticle impacts to an elastic–plastic model to develop a more thorough understanding of the transition between the regimes of rebound and bonding. We first extract an effective dynamic yield strength for copper from prior experiments impacting alumina spheres onto copper substrates. We then use this dynamic yield strength to analyze impacts of copper particles on copper substrates. We find that up to moderate impact velocities, impacts and rebound velocities follow a power-law behavior well-predicted on the basis of elastic-perfectly plastic analysis and can be captured well with a single value for the dynamic strength that subsumes many details not explicitly modeled (rate and hardening effects and adiabatic heating). However, the rebound behavior diverges from the power-law at higher impact velocities approaching bonding, where jetting sets on. This divergence is associated with additional lost kinetic energy, which goes into the ejection of the material associated with jetting and into breaking incipient bonds between the particle and substrate. These results further support and develop the idea that jetting facilitates bonding where a critical amount of bond formation is required to effect permanent particle deposition and prevent the particle from rebounding.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Temperature-Dependent Sheet and Contact Resistivity Measurements on Ag and Ag-Ni Circuit Pastes

The metal circuits and brazes used in electronic, energy conversion, and/or energy storage devices often have difficulty wetting and adhering to ceramic and/or ceramic-passivated metal substrates. Here, a novel Particle Interlayer Directed Wetting and Spreading (PIDWAS) technique is demonstrated that utilizes screen printing, the low wetting angle of silver on nickel, and the high work of adhesion between nickel and various ceramics to produce well-adhered, self-assembled silver patterns on ceramic and/or stainless-steel substrates not normally wet by silver. The resulting Ag-Ni circuits have higher sapphire adhesion strengths (up to 30 MPa on sapphire), higher densities (>97% on sapphire), and similar high-temperature electronic resistivities to those made using commercially-available Heraeus C8710 or DAD-87 silver circuit pastes. Similarly, Ag-Ni brazes between a variety of ceramic and/or stainless-steel substrates have better microstructural stability with rapid thermal cycling, reduction-oxidation cycling, and dual atmosphere isothermal aging than conventional Ag-CuO brazes. In addition, the residual Ni in these Ag-Ni circuits and brazes can be used to chemically getter surface segregated Al, ensuring low contact resistances on a variety of chromia- and/or alumina-passivated stainless steels. Reference: [1] Hu G, Zhou Q, Bhatlawande A, Park J, Termuhlen R, Ma Y, Bieler TR, Yu HC, Qi Y, Hogan T & Nicholas JD. Patterned Nickel Interlayers for Enhanced Silver Wetting, Spreading and Adhesion on Ceramic Substrates. Scripta Materialia, 2021; 196, 113767. 10.1016/j.scriptamat.2021.113767 [2] Park J, Phongpreecha T, Nicholas JD & Qi Y. Enhanced Liquid Metal Wetting on Oxide Surfaces via Patterned Particles. Acta Materialia, 2020; 199, 551-560. 10.1016/j.actamat.2020.08.037

Bhatlawande, Aishwarya↗
DOE OSTI2021

Ordered nanotubes on a two-dimensional substrate consisting of different material properties

A nanoscale conductor/semiconductor/insulator device includes a substrate with a lattice and a plurality of nanotubes in crystallographic alignment with the lattice at an interface between the plurality of nanotubes and the substrate. Another such device includes a substrate, meandering tracks in the substrate and a plurality of nanotubes adhering to cut-atomic-step edges of the meandering tracks. Methods of making the nanoscale conductor/semiconductor/insulator devices are also disclosed.

Nasseri, Mohsen↗