scholarly journals Thermal Insulation Properties of Hollow Y2O3:Eu Spheres Laminated with Er2O3

2021 ◽  
Author(s):  
YanXin Dan ◽  
Atsushi Nakamura ◽  
Hidetoshi Saitoh ◽  
Hua Li
Keyword(s):  
Composite Film ◽  
Thermal Insulation ◽  
Hollow Sphere ◽  
Hollow Spheres ◽  
Temperature Drop ◽  
Composite Films ◽  
Mass Ratio ◽  
Cross Sectional ◽  
Substrate Distance ◽  
Steady State Method

Abstract Currently, hollow sphere insulating materials are of importance for applications such as energy storage and savings and cryogenic engineering. The structures are formed by single hollow spheres, which can be joined, for example, by sintering. In this study, a 15 wt% Er-EDTA complex aqueous solution in which hollow Y2O3 spheres were mixed was used as the deposition body, and pencil spraying and sintering (PSS) was used to synthesize an Er2O3 hollow Y2O3 sphere composite film on a polished Si substrate. The structure of the composite film was successfully controlled by adjusting the 15 wt% Er-EDTA solution/hollow Y2O3 sphere mass ratio and the jet-to-substrate distance in the PSS process. In addition, the thermal insulation capability of the films was evaluated by the thermal steady-state method. The results show that the Er2O3/hollow Y2O3:Eu sphere composite films have a higher thermal insulation capability at a jet-to-substrate distance of 150 mm and a mass ratio (g) of 3.5:1. For the composite films with thicknesses of 38–92 µm, cross-sectional hollow ratio of 0.8–8.7% and void ratio of 6.3–13.1%, the temperature drop due to the porous (including hollow spheres and voids) structure films at 440°C is ΔTf =47°C. This is mainly associated with the film having more complicated microstructures. Therefore, the Er2O3/Y2O3:Eu composite film has good thermal insulation performance, and a simple preparation method for many kinds of hollow sphere films with complex structures and high porosities by using complex solutions with different compositions is provided.

Deposition and Tribological Properties of CVD Diamond/Diamond-Like Carbon Composite Films

2012 ◽  
Vol 565 ◽  
pp. 615-620
Author(s):  
Bin Shen ◽  
Liang Wang ◽  
Su Lin Chen ◽  
Fang Hong Sun
Keyword(s):  
Surface Morphology ◽  
Composite Film ◽  
Tribological Properties ◽  
Composite Films ◽  
Cvd Diamond ◽  
Carbon Composite ◽  
Dry Sliding ◽  
Diamond Like Carbon ◽  
Dlc Film ◽  
Bonding State

The CVD diamond/diamond-like carbon composite film is fabricated on the WC-Co substrate by depositing a layer of Diamond-like Carbon film on the surface of conventional Micro- or Nano-crystalline diamond film. The hot filament chemical vapor deposition (HFCVD) method and vacuum arc discharge with a graphite cathode are adopted respectively to deposit the MCD/NCD and DLC films. A variety of characterization techniques, including filed emission scanning electron microscope (FE-SEM) and Raman spectroscopy are employed to investigate the surface morphology and atomic bonding state of as-deposited MCD/DLC and NCD/DLC composite film. The results show that both MCD/DLC and NCD/DLC composite films present similar surface morphology with the MCD and NCD films, except for scattering a considerable amount of small-sized diamond crystallites among the grain boundary area. The atomic-bonding state of as-deposited MCD/DLC and NCD/DLC composite films is determined by the top-layered DLC film, which is mainly consisted of amorphous carbon phase and no discernible sp3 characteristic peak can be observed from their Raman spectrum. Furthermore, the tribological properties of as-deposited MCD/DLC and NCD/DLC composite films is examined using a ball-on-plate reciprocating friction tester under both dry sliding and water-lubricating conditions, comparing with conventional DLC, MCD and NCD films. Silicon nitride balls are used as counterpart materials. For the CVD diamond/DLC composite films, the self-lubricating effect of top-layered DLC film is beneficial for suppressing the initial friction peak, as well as shortening the run-in period. The average friction coefficients of MCD/DLC and NCD/DLC composite films during stable sliding period are 0.07 and 0.10 respectively in dry sliding; while under water-lubricating condition, they further decreases to 0.03 and 0.07.

scholarly journals Boosting Performance of Self-Polarized Fully Printed Piezoelectric Nanogenerators via Modulated Strength of Hydrogen Bonding Interactions

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1908
Author(s):  
Hai Li ◽  
Sooman Lim
Keyword(s):  
Hydrogen Bonding ◽  
Composite Film ◽  
High Performance ◽  
Composite Films ◽  
Β Phase ◽  
Hydrogen Bonding Interactions ◽  
Barium Titanate Nanoparticles ◽  
Surface Modified ◽  
Piezoelectric Devices ◽  
Piezoelectric Nanogenerators

Self-polarized piezoelectric devices have attracted significant interest owing to their fabrication processes with low energy consumption. Herein, novel poling-free piezoelectric nanogenerators (PENGs) based on self-polarized polyvinylidene difluoride (PVDF) induced by the incorporation of different surface-modified barium titanate nanoparticles (BTO NPs) were prepared via a fully printing process. To reveal the effect of intermolecular interactions between PVDF and NP surface groups, BTO NPs were modified with hydrophilic polydopamine (PDA) and hydrophobic 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES) to yield PDA-BTO and PFD-BTO, respectively. This study demonstrates that the stronger hydrogen bonding interactions existed in PFD-BTO/PVDF composite film comparative to the PDA-BTO/PVDF composite film induced the higher β-phase formation (90%), which was evidenced by the XRD, FTIR and DSC results, as well as led to a better dispersion of NPs and improved mechanical properties of composite films. Consequently, PFD-BTO/PVDF-based PENGs without electric poling exhibited a significantly improved output voltage of 5.9 V and power density of 102 μW cm−3, which was 1.8 and 2.9 times higher than that of PDA-BTO/PVDF-based PENGs, respectively. This study provides a promising approach for advancing the search for high-performance, self-polarized PENGs in next-generation electric and electronic industries.

scholarly journals Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Weihua Gu ◽  
Jiaqi Sheng ◽  
Qianqian Huang ◽  
Gehuan Wang ◽  
Jiabin Chen ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Thermal Insulation ◽  
Freeze Drying ◽  
Thermal Infrared ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
List Type ◽  
Drying Method ◽  
Cross Sectional ◽  
Compression Resistance

Highlights The eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method. Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel. Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition. . Abstract Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

scholarly journals Significantly Improved Dielectric Performance of Poly(1-butene)-Based Composite Films via Filling Polydopamine Modified Ba(Zr0.2Ti0.8)O3-Coated Multiwalled Carbon Nanotubes Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 285
Author(s):  
Lingfei Li ◽  
Qiu Sun ◽  
Xiangqun Chen ◽  
Zhaohua Jiang ◽  
Yongjun Xu
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Energy Storage ◽  
Composite Film ◽  
Multiwalled Carbon Nanotubes ◽  
Sol Gel ◽  
Composite Films ◽  
Weak Electric Field ◽  
Multiwalled Carbon ◽  
Dielectric Performance

The low dielectric constant of the nonpolar polymer poly(1-butene) (PB-1) limits its application as a diaphragm element in energy storage capacitors. In this work, Ba(Zr0.2Ti0.8)O3-coated multiwalled carbon nanotubes (BZT@MWCNTs) were first prepared by using the sol–gel hydrothermal method and then modified with polydopamine (PDA) via noncovalent polymerization. Finally, PB-1 matrix composite films filled with PDA-modified BZT@MWCNTs nanoparticles were fabricated through a solution-casting method. Results indicated that the PDA-modified BZT@MWCNTs had good dispersion and binding force in the PB-1 matrix. These characteristics improved the dielectric and energy storage performances of the films. Specifically, the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film exhibited the best dielectric performance. At 1 kHz, the dielectric constant of this film was 25.43, which was 12.7 times that of pure PB-1 films. Moreover, its dielectric loss was 0.0077. Furthermore, under the weak electric field of 210 MV·m−1, the highest energy density of the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film was 4.57 J·cm−3, which was over 3.5 times that of PB-1 film (≈1.3 J·cm−3 at 388 MV·m−1).

Enhanced thermal conductivity of polyimide composite film filled with hybrid fillers

2021 ◽  
pp. 095400832110003
Author(s):  
Ruiyi Li ◽  
Chengcheng Ding ◽  
Juan Yu ◽  
Xiaodong Wang ◽  
Pei Huang
Keyword(s):  
Thermal Conductivity ◽  
Composite Film ◽  
Hexagonal Boron Nitride ◽  
Composite Films ◽  
Resistance Index ◽  
Reference Value ◽  
Residual Rate ◽  
Practical Applications ◽  
Hybrid Fillers ◽  
The Matrix

In this article, the polyimide (PI) composite films with synergistically improving thermal conductivity were prepared by adding a few graphene nanoplatelets (GNP) and various hexagonal boron nitride (h-BN) contents into the PI matrix. The thermal conductivity of PI composite film with 1 wt% GNP and 30 wt% h-BN content was 1.21 W(m·k)− 1, which was higher than that of the PI composite film with 30 wt% h-BN content (0.45 W(m·k)− 1), the synergistic efficiency of GNP under various h-BN content (10 wt%, 20 wt%, and 30 wt%) were 1.70, 2.71, and 3.09, respectively. And it was found that the increased h-BN content can suppress the dielectric properties caused by GNP in the matrix. The dielectric permittivity and dielectric loss tangent of 1 wt% GNP/PI composite film were 10.69, 0.661 at 103 Hz, respectively, and that of the 30 wt% h-BN + GNP/PI composite film were 4.29 and 0.1367, respectively. Moreover, the mechanical properties of the PI composite film were suitable for practical applications. And the heat resistance index and the residual rate at 700°C of PI composite film increased to 326.8°C, 74.43%, respectively, and these of PI film were 292.6°C and 59.26%. Thus, it may provide a reference value for applying the filler hybridization/PI film in the electronic packaging materials.

scholarly journals Ecofriendly Preparation and Characterization of a Cassava Starch/Polybutylene Adipate Terephthalate Film

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 329
Author(s):  
Tan Yi ◽  
Minghui Qi ◽  
Qi Mo ◽  
Lijie Huang ◽  
Hanyu Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Water Vapor ◽  
Composite Film ◽  
Water Absorption ◽  
Composite Films ◽  
Thermoplastic Starch ◽  
Light Transmittance ◽  
Infrared Spectrometry ◽  
Nano Zno

Composite films of polybutylene adipate terephthalate (PBAT) were prepared by adding thermoplastic starch (TPS) (TPS/PBAT) and nano-zinc oxide (nano-ZnO) (TPS/PBAT/nano-ZnO). The changes of surface morphology, thermal properties, crystal types and functional groups of starch during plasticization were analyzed by scanning electron microscopy, synchronous thermal analysis, X-ray diffraction, infrared spectrometry, mechanical property tests, and contact Angle and transmittance tests. The relationship between the addition of TPS and the tensile strength, transmittance, contact angle, water absorption, and water vapor barrier of the composite film, and the influence of nano-ZnO on the mechanical properties and contact angle of the 10% TPS/PBAT composite film. Experimental results show that, after plasticizing, the crystalline form of starch changed from A-type to V-type, the functional group changed and the lipophilicity increased; the increase of TPS content, the light transmittance and mechanical properties of the composite membrane decreased, while the water vapor transmittance and water absorption increased. The mechanical properties of the composite can be significantly improved by adding nano-ZnO at a lower concentration (optimum content is 1 wt%).

The Effect of Scattering Layer on the Performance of Dye-Sensitized Solar Cells Using TiO2 Hollow Spheres/TiO2 Nanoparticles Films as Photoanodes

2015 ◽  
Vol 15 (10) ◽  
pp. 8295-8298 ◽  
Author(s):  
Su Kyung Park ◽  
Soong-Hyuck Suh ◽  
Min Woo Lee ◽  
Tae Kwan Yun ◽  
Jae Young Bae
Keyword(s):  
Solar Cells ◽  
Hollow Spheres ◽  
Composite Films ◽  
Dye Sensitized Solar Cells ◽  
Layered Composite ◽  
Photoelectric Conversion ◽  
Dye Sensitized ◽  
Nanoparticle Layer ◽  
Promising Development ◽  
Sensitized Solar Cells

TiO2 hollow spheres were successfully synthesized using poly styrene as the template. Dyesensitized solar cells are fabricated based on double-layered composite films of TiO2 nanoparticles and TiO2 hollow spheres. The photoelectric conversion performances of Dye-sensitized solar cells based on TiO2 nanoparticles/TiO2 nanoparticles, TiO2 nanoparticles/TiO2 hollow spheres and TiO2 hollow spheres/TiO2 hollow spheres double-layered films are investigated, and their photoelectric conversion efficiencies were determined to 4.52, 7.10 and 5.48%, respectively. Dye-sensitized solar cells based on double layered composite films of TiO2 nanoparticles and TiO2 hollow spheres exhibit the highest photo-electric conversion efficiency mainly due to the combined effect of two factors, the high light scattering of over-layer hollow spheres that enhance harvesting light of the Dye-sensitized solar cells and the under-layer TiO2 nanoparticle layer that ensures good electronic contact between TiO2 film and FTO conducting glass. The double layered composite TiO2 film electrodes are a promising development in enhancing the performance of dye-sensitized solar cells.

The Preparation and Property Research on Laponite-Poly (L-Lactide) Composite Film

2013 ◽  
Vol 750-752 ◽  
pp. 1919-1923 ◽  
Author(s):  
Guo Xian Zhou ◽  
Ming Wei Yuan ◽  
Lin Jiang ◽  
Ming Long Yuan ◽  
Hong Li Li
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Composite Film ◽  
Composite Films ◽  
Complexing Agent ◽  
Solution Blending ◽  
Method Of Solution ◽  
Thermal Stability Of ◽  
Scanning Electron

The laponite-poly (L-lactide) composite films are prepared by the method of solution blending with polylactide (PLA) and laponite. The result shows that the homogeneous and smooth composite film is prepared with 1, 4-dioxane. Thermogravimetry analysis (TG) and tensile strength studies demonstrate that the thermal stability and tensile strength are improved with the laponite added. The scanning electron microscopy (SEM) measurement indicates that the pores of composite films get uniform and network structure is more and more compact with compared to pure PLA film. The present study reveals that the laponite as a complexing agent can improve the mechanical properties and thermal stability of PLA.

scholarly journals Effect of High Pressure Treatment on Poly(lactic acid)/Nano–TiO2 Composite Films

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2621 ◽  
Author(s):  
Hai Chi ◽  
Wenhui Li ◽  
Chunli Fan ◽  
Cheng Zhang ◽  
Lin Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Lactic Acid ◽  
Composite Film ◽  
Composite Films ◽  
Barrier Properties ◽  
Poly Lactic Acid ◽  
Pressure Treatment ◽  
Nano Tio2 ◽  
High Pressure Treatment

The microstructure, thermal properties, mechanical properties and oxygen and water vapor barrier properties of a poly(lactic acid) (PLA)/nano-TiO2 composite film before and after high pressure treatment were studied. Structural analysis showed that the functional group structure of the high pressure treated composite film did not change. It was found that the high pressure treatment did not form new chemical bonds between the nanoparticles and the PLA. The micro-section of the composite film after high pressure treatment became very rough, and the structure was depressed. Through the analysis of thermal and mechanical properties, high pressure treatment can not only increase the strength and stiffness of the composite film, but also increase the crystallinity of the composite film. Through the analysis of barrier properties, it is found that the barrier properties of composite films after high pressure treatment were been improved by the applied high pressure treatment.

scholarly journals Actuation Behavior of Multilayer Graphene Nanosheets/Polydimethylsiloxane Composite Films

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1243 ◽  
Author(s):  
Chunmei Zhang ◽  
Tianliang Zhai ◽  
Chao Zhan ◽  
Qiuping Fu ◽  
Chao Ma
Keyword(s):  
Composite Film ◽  
High Performance ◽  
Graphene Nanosheets ◽  
Composite Films ◽  
Multilayer Graphene ◽  
Layer By Layer ◽  
Pdms Film ◽  
Out Of Plane ◽  
Dielectric Actuation ◽  
Electromechanical Actuation

The graphene nanosheets (GNS)/polydimethylsiloxane (PDMS) composite films with out-of-plane dielectric actuation behavior were prepared through a layer-by-layer spin coating process. The GNS-PDMS/PDMS composite films with 1~3 layers of GNS-PDMS films were spin coated on top of the PDMS film. The dielectric, mechanical, and electromechanical actuation properties of the composite films were investigated. The dielectric constant of the GNS-PDMS3/PDMS composite film at 1 kHz is 5.52, which is 1.7 times that of the GNS-PDMS1/PDMS composite film. The actuated displacement of the GNS-PDMS/PDMS composite films is greatly enhanced by increasing the number of GNS-PDMS layers. This study provides a novel alternative approach for fabricating high-performance actuators with out-of-plane actuation behavior.

Sign in / Sign up

Export Citation Format

Share Document