Ultralow secondary electron emission and improved vacuum surface insulation of polyimide with scalable nanocomposite coating

Yang, Xiong; Sun, Guangyu; Zhou, Run-Dong; Huang, Kun; Li, Wendong; Wang, Chao; Dong, Jiufeng; Song, Bai‐Peng; Zhang, Guanjun

doi:10.1016/j.apsusc.2022.153221

Cited by 26 publications

(20 citation statements)

References 56 publications

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“…Sub-surface charge migration is regulated by the trap states, which affects the above-surface process of flashover development, including SEEA, surface charging, and outgassing, and ultimately determines the surface insulation. On the one hand, the trap density and energy levels could affect the SEY by changing the trapping escape mean free path and probability of the internal SEs excited by the incident electrons (Figure d). , It has been demonstrated that the increase in trap density always yields lower SEE for a positively charged dielectric surface, which is preferable for better surface insulation. Deep trap states mainly impede surface charge emission to alleviate the surface charging and hence increase flashover voltage, which is more pronounced with higher deep trap state density and the trap energy level.…”

Section: Resultsmentioning

confidence: 99%

“…Finally, V app is decreased step by step (1 kV each step) until no flashover occurred under each pulse, noted as the hold-off voltage ( U ho ). A standard three-electrode system (8009 resistivity test fixture) connected to a high-resolution electrometer (Keithley 6517B) was used to test the surface resistivity. , …”

Section: Methodsmentioning

confidence: 99%

“…A standard three-electrode system (8009 resistivity test fixture) connected to a high-resolution electrometer (Keithley 6517B) was used to test the surface resistivity. 31,35 Figure S2 shows a schematic of the surface potential distribution measurement system, which is composed of a duo-axis displacement platform and a Kelvin probe (Trek 3455ET) operated by an electrostatic voltmeter (Trek 341B) connected to the abovementioned flashover test platform. The electrode-sample configuration used for the surface potential measurement in this study is shown in Figure S3b.…”

Section: Preparation Of Hybrid Nanocomposite Filmsmentioning

confidence: 99%

“…Extensive attempts have been made to improve vacuum surface insulation, for example, creating microstructures on the surface, − coatings that facilitate surface charge dissipation, − and materials with low secondary electron yield (SEY). − Surface microstructures (e.g., nonperiodic roughness, pores, and grooves) mitigate flashover by blocking the propagation of the SEEA. , Yet producing microstructures is generally not applicable for flexible films because the microstructure dimensions are usually comparable to or greater than the film thickness (∼ tens of μm). Coatings improving the surface conductivity can facilitate surface charge dissipation, especially in repetitive discharges.…”

Section: Introductionmentioning

confidence: 99%

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Tailoring Organic/Inorganic Interface Trap States of Metal Oxide/Polyimide toward Improved Vacuum Surface Insulation

Yang,

Sun,

Guo

et al. 2023

ACS Appl. Mater. Interfaces

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High-voltage and high-power devices are indispensable in spacecraft for outer space explorations, whose operations require aerospace materials with adequate vacuum surface insulation performance. Despite persistent attempts to fabricate such materials, current efforts are restricted to trial-and-error methods and a universal design guideline is missing. The present work proposes to improve the vacuum surface insulation by tailoring the surface trap state density and energy level of the metal oxides with varied bandgaps, using coating on a polyimide (PI) substrate, aiming for a more systematical workflow for the insulation material design. First-principle calculations and trap diagnostics are employed to evaluate the material properties and reveal the interplay between trap states and the flashover threshold, supported by dedicated analyses of the flashover voltage, secondary electron emission (SEE) from insulators, and surface charging behaviors. Experimental results suggest that the coated PI (i.e., CuO@PI, SrO@PI, MgO@PI, and Al2O3@PI) can effectively increase the trap density and alter the trap energy levels. Elevated trap density is demonstrated to always yield lower SEE. In addition, increasing shallow trap density accelerates surface charge dissipation, which is favorable for improving surface insulation. CuO@PI exhibits the most remarkable increase in shallow trap density, and accordingly, the highest flashover voltage is 42.5% higher than that of pristine PI. This study reveals the critical role played by surface trap states in flashover mitigation and offers a novel strategy to optimize the surface insulation of materials.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Preparation Of Hybrid Nanocomposite Filmsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tailoring Organic/Inorganic Interface Trap States of Metal Oxide/Polyimide toward Improved Vacuum Surface Insulation

Yang,

Sun,

Guo

et al. 2023

ACS Appl. Mater. Interfaces

Self Cite

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“…Kelvin probe is always perpendicular to the sample plane with a ~2 mm fixed space between the probe and the sample surface to acquire a high resolution during the whole scanning process. The scanning trajectory of the probe is a zigzag scanning route and covers a region of 40 � 30 mm at the sample surface after a certain impulse number N. More details of the experiment system and measurement procedures can be found in our previous study [46]. It is worth mentioning that the dissipation of surface charge in vacuum can be neglected during the complete scanning process of 5 min.…”

Section: Characterisationmentioning

confidence: 99%

Design and 3D printing of porous cavity insulation structure for ultra‐high electrical withstanding capability

et al. 2023

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Vacuum‐dielectric interface is the most vulnerable part of vacuum insulation systems where surface electrical breakdown is prone to happen, hence severely restricts the development of advanced electro‐vacuum devices with large capacity and its miniaturisation. Generally, a direct and effective way to improve vacuum surface insulation is to alleviate the initiation and development of multipactor phenomena. Inspired by this approach, the authors report a 3D‐printed insulation structure designed with a millimetre‐scale surface cavity covered by periodic through‐pore array via stereolithography, exhibiting remarkable multipactor suppression and flashover threshold improvement, well outperforming the conventional flashover mitigation strategies. Experiments and simulations demonstrate that electrons in the multipactor region pass through‐pores and are unlikely to escape from the cavity, hence no longer participate in the above‐surface multipactor process, and eventually improve flashover threshold. The proposed approach provides new inspiration for the design of advanced insulators featuring ultra‐high electrical withstanding capability and brings up new insight into pertinent industrial applications.

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The fluorinated SiO₂ self‐assembly surface of epoxy resin with excellent insulating and superhydrophobic properties

et al. 2023

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The flashover and dampness on the surface of epoxy resin (ER) composites are two critical factors leading to the failure of high voltage direct current (HVDC) insulating devices. Designing and constructing a surface structure with high insulating and hydrophobic performance is an effective way to solve these problems. In this paper, we prepared fluorinated silica nanoparticles (F‐SiO2) using a combination of dielectric barrier discharge (DBD) plasma and 1H,1H,2H,2H‐Perfluorodecyltrimethoxysilane (FAS‐17). The resulting low‐surface‐energy F‐SiO2 self‐assembled on the surface of ER to form a thin layer structure. Our results demonstrate a significant improvement in both the surface flashover voltage and hydrophobicity of ER composites with the self‐assembly structure. The maximum surface flashover voltage is increased by 35.73% to 12.08 kV, and the maximum water contact angle reaches superhydrophobicity at 155.5 ± 3°. The improvements in flashover voltage are attributed to changes in trap energy level and surface roughness. At the same time, the superhydrophobicity is due to the low‐surface‐energy characteristics and micro‐nano structure of the self‐assembly structure. This study provides a promising approach for synergistically improving flashover voltage and hydrophobicity of insulating materials.

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Ultralow secondary electron emission and improved vacuum surface insulation of polyimide with scalable nanocomposite coating

Cited by 26 publications

References 56 publications

Tailoring Organic/Inorganic Interface Trap States of Metal Oxide/Polyimide toward Improved Vacuum Surface Insulation

Tailoring Organic/Inorganic Interface Trap States of Metal Oxide/Polyimide toward Improved Vacuum Surface Insulation

Design and 3D printing of porous cavity insulation structure for ultra‐high electrical withstanding capability

The fluorinated SiO₂ self‐assembly surface of epoxy resin with excellent insulating and superhydrophobic properties

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Ultralow secondary electron emission and improved vacuum surface insulation of polyimide with scalable nanocomposite coating

Cited by 26 publications

References 56 publications

Tailoring Organic/Inorganic Interface Trap States of Metal Oxide/Polyimide toward Improved Vacuum Surface Insulation

Tailoring Organic/Inorganic Interface Trap States of Metal Oxide/Polyimide toward Improved Vacuum Surface Insulation

Design and 3D printing of porous cavity insulation structure for ultra‐high electrical withstanding capability

The fluorinated SiO2 self‐assembly surface of epoxy resin with excellent insulating and superhydrophobic properties

Contact Info

Product

Resources

About

The fluorinated SiO₂ self‐assembly surface of epoxy resin with excellent insulating and superhydrophobic properties