Study of Droplet Diffusion in Hydrothermal-Assisted Transient Jet Fusion of Ceramics

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Fan Fei ◽  
Li He ◽  
Levi Kirby ◽  
Xuan Song
Keyword(s):  
High Performance ◽  
Functional Materials ◽  
Processing Parameters ◽  
Layer By Layer ◽  
Transient Solution ◽  
Powder Bed ◽  
Precise Control ◽  
Powder Packing ◽  
And Diffusion ◽  
Diffusion Profiles

Abstract Hydrothermal-assisted transient jet fusion (HTJF) is a powder-based additive manufacturing (AM) method of ceramics, which utilizes a water-mediated hydrothermal mechanism to fuse particles together, eliminating the use of organic binders in forming green bodies and thereby contributing to high green-density parts (>90%) advantageous for fabricating functional materials with high performance. In the HTJF process, a transient solution such as water is selectively deposited into a powder bed in a layer-by-layer fashion followed by a hydrothermal fusion process. Upon the ejection and deposition of a droplet of the transient solution on the surface of the powder bed, the diffusion behavior of the liquid significantly influences the particle fusion and the fabrication accuracy of the HTJF process. Precise control of the liquid diffusion in the powder bed is critical for the fabrication of ceramic structures with both high density and accuracy. In this paper, the dependence of transient solution diffusion on different process parameters (i.e., powder packing density, droplet size, pressure, etc.) in the HTJF process were studied. Both numerical modeling and experimental methods were used to quantify the relationships between processing parameters and diffusion profiles of transient solution droplets (e.g., diffusion width/depth). Optimum processing conditions were identified to mitigate the undesired diffusion of transient solution droplets in the powder bed.

Study of Droplet Diffusion in Hydrothermal-Assisted Transient Jet Fusion of Ceramics

2020 ◽  
Author(s):  
Fan Fei ◽  
Li He ◽  
Levi Kirby ◽  
Xuan Song
Keyword(s):  
High Performance ◽  
Functional Materials ◽  
Processing Parameters ◽  
Layer By Layer ◽  
Transient Solution ◽  
Powder Bed ◽  
Manufacturing Method ◽  
Precise Control ◽  
Powder Packing ◽  
Diffusion Profiles

Abstract Hydrothermal-assisted transient jet fusion (HTJF) is a powder-based additive manufacturing method of ceramics, which utilizes a water-mediated hydrothermal mechanism to fuse particles together, eliminating the use of organic binders in forming green bodies and thereby contributing to high green-density parts (> 90%) advantageous for fabricating functional materials with high-performance. In the HTJF process, a transient solution such as water is selectively deposited into a powder bed in a layer-by-layer fashion followed by a hydrothermal fusion process. Upon the ejection and deposition of a droplet of the transient solution on the surface of the powder bed, the diffusion behavior of the liquid significantly influences the particle fusion and the fabrication accuracy of the HTJF process. Precise control of the liquid diffusion in the powder bed is critical for the fabrication of ceramic structures with both high density and accuracy. In this paper, the dependence of transient solution diffusion on different process parameters (i.e., powder packing density, droplet size, pressure, etc.) in the HTJF process were studied. Both numerical modeling and experimental methods were used to quantify the relationships between processing parameters and diffusion profiles of transient solution droplets (e.g., diffusion width/depth). Optimum processing conditions were identified to mitigate the undesired diffusion of transient solution droplets in the powder bed.

scholarly journals Detection of Typical Metal Additive Manufacturing Defects by the Application of Thermographic Techniques

Proceedings ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 24
Author(s):  
D’Accardi ◽  
Altenburg ◽  
Maierhofer ◽  
Palumbo ◽  
Galietti
Keyword(s):  
Additive Manufacturing ◽  
Processing Parameters ◽  
Layer By Layer ◽  
Metal Powders ◽  
Destructive Testing ◽  
Powder Bed ◽  
Manufacturing Defects ◽  
Metal Additive Manufacturing ◽  
Time Required ◽  
Metal Additive

One of the most advanced technologies of Metal Additive Manufacturing (AM) is the Laser Powder Bed Fusion process (L-PBF), also known as Selective Laser Melting (SLM). This process involves the deposition and fusion, layer by layer, of very fine metal powders and structure and quality of the final component strongly depends on several processing parameters, for example the laser parameters. Due to the complexity of the process it is necessary to assure the absence of defects in the final component, in order to accept or discard it. Thermography is a very fast non-destructive testing (NDT) technique. Its applicability for defect detection in AM produced parts would significantly reduce costs and time required for NDT, making it versatile and very competitive.

scholarly journals Scalable Production of Monodisperse Functional Microspheres by Multilayer Parallelization of High Aspect Ratio Microfluidic Channels

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 592 ◽  
Author(s):  
Casper Ho Yin Chung ◽  
Binbin Cui ◽  
Ruyuan Song ◽  
Xin Liu ◽  
Xiaonan Xu ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Large Scale ◽  
Scale Up ◽  
Functional Materials ◽  
Droplet Microfluidics ◽  
Microfluidic Channels ◽  
Layer By Layer ◽  
Precise Control ◽  
Wide Range

Droplet microfluidics enables the generation of highly uniform emulsions with excellent stability, precise control over droplet volume, and morphology, which offer superior platforms over conventional technologies for material synthesis and biological assays. However, it remains a challenge to scale up the production of the microfluidic devices due to their complicated geometry and long-term reliability. In this study, we present a high-throughput droplet generator by parallelization of high aspect ratio rectangular structures, which enables facile and scalable generation of uniform droplets without the need to precisely control external flow conditions. A multilayer device is formed by stacking layer-by-layer of the polydimethylsiloxane (PDMS) replica patterned with parallelized generators. By feeding the sample fluid into the device immersed in the carrying fluid, we used the multilayer device with 1200 parallelized generators to generate monodisperse droplets (~45 μm in diameter with a coefficient of variation <3%) at a frequency of 25 kHz. We demonstrate this approach is versatile for a wide range of materials by synthesis of polyacrylamide hydrogel and Poly (l-lactide-co-glycolide) (PLGA) through water-in-oil (W/O) and oil-in-water (O/W) emulsion templates, respectively. The combined scalability and robustness of such droplet emulsion technology is promising for production of monodisperse functional materials for large-scale applications.

Processing and Structural Characterization of Ferroelectric Thin Films Deposited by Ion Beam Sputtering

1990 ◽  
Vol 200 ◽  
Author(s):  
M. S. Ameen ◽  
T. M. Graettinger ◽  
S. H. Rou ◽  
H. N. Al-Shareef ◽  
K. D. Gifford ◽  
...  
Keyword(s):  
Ion Beam ◽  
Ferroelectric Properties ◽  
Processing Parameters ◽  
Layer By Layer ◽  
Ion Beam Sputtering ◽  
Target Holder ◽  
Feedback Information ◽  
Transparent Films ◽  
Precise Control ◽  
Crystal Resonator

ABSTRACTAn analysis is presented of the ion beam sputter deposition of ferroelectric KNbO3 and Pb(Zr, Ti)O3 (PZT), and the observed compositional, structural, and microstructural properties of these films. Films are deposited using a specially designed computer-controlled system with ability to produce multicomponent films via layer-by-layer deposition of elemental components. Metal or oxide targets are sequentially exposed to a high current ion beam by means of a rotatable target holder. A quartz crystal resonator provides feedback information on layer thicknesses to the computer. Precise control of film stoichiometry is obtained using this method.KNbO3, a material possessing a high figure-of-merit for electrooptic applications, has been deposited epitaxially on (100) MgO substrates. The structure of the optically transparent films has been studied with x-ray and electron diffraction, and transmission electron microscopy. The effects of various processing parameters on the microstructure of the films are discussed.We have demonstrated the ability of the technique to produce multicomponent films and control cation concentration at elevated substrate temperatures for materials such as PZT. The microstructure and associated ferroelectric properties are discussed in relation to processing conditions.

scholarly journals A Windmill-Shaped Molecule with Anthryl Blades to Form Smooth Hole-Transport Layers via a Photoprecursor Approach

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2316
Author(s):  
Akihiro Maeda ◽  
Aki Nakauchi ◽  
Yusuke Shimizu ◽  
Kengo Terai ◽  
Shuhei Sugii ◽  
...  
Keyword(s):  
Thin Film ◽  
High Performance ◽  
Molecular Design ◽  
Layer Structure ◽  
Hole Transport ◽  
Layer By Layer ◽  
Precise Control ◽  
Wet Processing ◽  
Improved Performance ◽  
Controlled Deposition

Preparation of high-performance organic semiconductor devices requires precise control over the active-layer structure. To this end, we are working on the controlled deposition of small-molecule semiconductors through a photoprecursor approach wherein a soluble precursor compound is processed into a thin-film form and then converted to a target semiconductor by light irradiation. This approach can be applied to layer-by-layer solution deposition, enabling the preparation of p–i–n-type photovoltaic active layers by wet processing. However, molecular design principles are yet to be established toward obtaining desirable thin-film morphology via this unconventional method. Herein, we evaluate a new windmill-shaped molecule with anthryl blades, 1,3,5-tris(5-(anthracen-2-yl)thiophen-2-yl)benzene, which is designed to deposit via the photoprecursor approach for use as the p-sublayer in p–i–n-type organic photovoltaic devices (OPVs). The new compound is superior to the corresponding precedent p-sublayer materials in terms of forming smooth and homogeneous films, thereby leading to improved performance of p–i–n OPVs. Overall, this work demonstrates the effectiveness of the windmill-type architecture in preparing high-quality semiconducting thin films through the photoprecursor approach.

scholarly journals Elevating silicon into a high performance nonlinear optical platform through the integration of 2D graphene oxide thin films

2021 ◽  
Author(s):  
David Moss
Keyword(s):  
High Performance ◽  
Nonlinear Optical ◽  
Kerr Nonlinearity ◽  
Photonic Devices ◽  
Silicon On Insulator ◽  
Layer By Layer ◽  
Large Area ◽  
Precise Control ◽  
Highly Nonlinear ◽  
Coating Method

Abstract Layered two-dimensional (2D) GO films are integrated with silicon-on-insulator (SOI) nanowire waveguides to experimentally demonstrate an enhanced Kerr nonlinearity, observed through self-phase modulation (SPM). The GO films are integrated with SOI nanowires using a large-area, transfer-free, layer-by-layer coating method that yields precise control of the film thickness. The film placement and coating length are controlled by opening windows in the silica cladding of the SOI nanowires. Owing to the strong mode overlap between the SOI nanowires and the highly nonlinear GO films, the Kerr nonlinearity of the hybrid waveguides is significantly enhanced. Detailed SPM measurements using picosecond optical pulses show significant spectral broadening enhancement for SOI nanowires coated with 2.2-mm-long films of 1 − 3 layers of GO, and 0.4-mm-long films with 5 − 20 layers of GO. By fitting the experimental results with theory, the dependence of GO’s n2 on layer number and pulse energy is obtained, showing interesting physical insights and trends of the layered GO films from 2D monolayers to quasi bulk-like behavior. Finally, we show that by coating SOI nanowires with GO films the effective nonlinear parameter of SOI nanowires is increased 16 fold, with the effective nonlinear figure of merit (FOM) increasing by about 20 times to FOM > 5. These results reveal the strong potential of using layered GO films to improve the Kerr nonlinear optical performance of silicon photonic devices.

Effect of Process Parameters on Compressive Properties of ULTEM 9085 Produced by FDM Process

2018 ◽  
Author(s):  
Aboma Wagari Gebisa ◽  
Hirpa G. Lemu
Keyword(s):  
Process Parameters ◽  
High Performance ◽  
Fused Deposition Modeling ◽  
Compressive Strain ◽  
Processing Parameters ◽  
Air Gap ◽  
Layer By Layer ◽  
Compressive Properties ◽  
Significant Interaction Effect ◽  
Fused Deposition

Fused deposition modeling (FDM), one of the additive manufacturing (AM) technologies, is a promising digital manufacturing technique that produces parts, layer by layer, by heating, extruding and depositing filaments of thermoplastic polymers. The properties of FDM-produced parts apparently depend on the processing parameters. These processing parameters have conflicting advantages that need to be investigated. This paper investigates the effect of process parameters on the compressive properties of parts produced by the FDM process. The study is carried out on a high performance polymeric material called ULTEM 9085. Full factorial design of experiment is used to analyze the effects of process parameters on the compressive properties of the material. Five parameters: namely, air gap, raster width, raster angle, contour number and contour width, of the FDM machine are considered in the current study. The results show that, with the exception of the raster width, all other considered parameters have significant interaction effect on the compressive strength. For the compressive strain, air gap, contour number and contour width showed substantial interaction effects.

scholarly journals Crystal Engineering Approach for Fabrication of Inverted Perovskite Solar Cell in Ambient Conditions

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1751
Author(s):  
Inga Ermanova ◽  
Narges Yaghoobi Nia ◽  
Enrico Lamanna ◽  
Elisabetta Di Bartolomeo ◽  
Evgeny Kolesnikov ◽  
...  
Keyword(s):  
Solar Cell ◽  
Crystal Engineering ◽  
High Performance ◽  
Perovskite Solar Cells ◽  
Perovskite Solar Cell ◽  
Layer By Layer ◽  
Ambient Conditions ◽  
Sequential Method ◽  
Engineering Approach ◽  
Hole Transporting

In this paper, we demonstrate the high potentialities of pristine single-cation and mixed cation/anion perovskite solar cells (PSC) fabricated by sequential method deposition in p-i-n planar architecture (ITO/NiOX/Perovskite/PCBM/BCP/Ag) in ambient conditions. We applied the crystal engineering approach for perovskite deposition to control the quality and crystallinity of the light-harvesting film. The formation of a full converted and uniform perovskite absorber layer from poriferous pre-film on a planar hole transporting layer (HTL) is one of the crucial factors for the fabrication of high-performance PSCs. We show that the in-air sequential deposited MAPbI3-based PSCs on planar nickel oxide (NiOX) permitted to obtain a Power Conversion Efficiency (PCE) exceeding 14% while the (FA,MA,Cs)Pb(I,Br)3-based PSC achieved 15.6%. In this paper we also compared the influence of transporting layers on the cell performance by testing material depositions quantity and thickness (for hole transporting layer), and conditions of deposition processes (for electron transporting layer). Moreover, we optimized second step of perovskite deposition by varying the dipping time of substrates into the MA(I,Br) solution. We have shown that the layer by layer deposition of the NiOx is the key point to improve the efficiency for inverted perovskite solar cell out of glove-box using sequential deposition method, increasing the relative efficiency of +26% with respect to reference cells.

scholarly journals Synthesis, Structure and Diffusion Pathways of Fast Lithium-Ion Conductors in the Polymorphs α- and β-Li8SnP4

2021 ◽  
Author(s):  
Thomas F Fässler ◽  
Stefan Strangmüller ◽  
Henrik Eickkhoff ◽  
Wilhelm Klein ◽  
Gabriele Raudaschl-Sieber ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Lithium Ion ◽  
Conducting Materials ◽  
Increasing Demand ◽  
Battery Technology ◽  
Lithium Ion Conductors ◽  
And Diffusion ◽  
Ion Conductors

The increasing demand for a high-performance and low-cost battery technology promotes the search for Li+-conducting materials. Recently, phosphidotetrelates and aluminates were introduced as an innovative class of phosphide-based Li+-conducting materials...

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

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