Two-Phase-Interfaced, Graded-Permittivity Titania Electrical Insulation by Atmospheric Pressure Plasmas

Kong, Fei; Zhao, Mingming; Zhang, Cheng; Ren, Chengyan; Ostrikov, Kostya Ken; Shao, Tao

doi:10.1021/acsami.1c18044

Cited by 32 publications

(11 citation statements)

References 67 publications

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“…Plasma surface modification is a recent emerging technology. It has flexible regulation, low energy consumption, and is environment friendly. , Thus, it is applied in the modification of microelectronics, metals, polymers, and biomaterials. , The active particles in plasma have a penetration depth of nanometers; thus, the plasma modification will not change the bulk properties of the substrate . Most of the particles produced by the discharge plasma have energies higher than the binding energy of common chemical bonds (C–C, H–O, C–O, CO, CC, etc.).…”

Section: Introductionmentioning

confidence: 99%

High Performance Epoxy Composites Containing Nanofiller Modified by Plasma Bubbles

Kong

Yan

Zhang

et al. 2023

ACS Appl. Mater. Interfaces

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The thermal conductivity of polymer materials is a fundamental parameter in the field of high-voltage electrical insulation. When the operating frequency and power for electrical equipment or electronic devices increase significantly, the internal heat will increase dramatically, and the accumulation of heat will further lead to insulation failure and serious damage of the whole system. The addition of filler with high thermal conductivity into polymer is a common solution. However, the interfacial thermal resistance between filler and bulk materials is the major obstacle to improve thermal conductivity. Herein, in order to reduce the interfacial thermal resistance, nanofillers are modified by plasma technology. The surface modification of nano-Al2O3 is carried out using plasma bubbles with three atmospheres (Ar, Ar+O2, air) as well as coupling agent. The situation of surface grafting before and after the modification is characterized using FTIR, XPS, and SEM. The effect of the mechanism of modification on the thermal conductivity and reaction pathway is investigated. The results showed that the thermal conductivity after plasma modification is increased significantly. Especially, the thermal conductivity is increased by 35% for the sample modified by Ar+O2 atmosphere. This results because more hydroxyl is introduced on the filler surface by the plasma bubbles, which enhance the interface compatibility between filler and epoxy. In addition, surface insulation performance for the modified samples also is enhanced by 14%. This is associated with the change of surface resistance and trap distribution. These results provide potential support for the development of fabrication for high performance epoxy composites.

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Section: Introductionmentioning

confidence: 99%

High Performance Epoxy Composites Containing Nanofiller Modified by Plasma Bubbles

Kong

Yan

Zhang

et al. 2023

ACS Appl. Mater. Interfaces

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“…Comparatively, multipactor suppression is the more direct, effective, and frequently used strategy, which is based on the design principle to reduce the secondary electron yield (SEY) of the insulators and reduce the number of electrons available for SEEA. The SEY reduction approaches, including bulk insulation modification (e.g., chemical grafting [24,25], doping of functional fillers [26,27]) and surface treatment (e.g., fluorination [28,29], composite coating [30][31][32][33], plasma treatment [34][35][36], and thin film deposition [37,38]) have shown the ability of multipactor suppression to some extent. Nevertheless, most of these methods are collectively cumbersome and have poor mechanical stability.…”

Section: Introductionmentioning

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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“…Alternatively, materials with lower SEY emit fewer SEs and hence accumulate less surface charge. The last two strategies usually focus on chemical modifications including composite coating, , doping of functional fillers, , fluorination, − plasma treatment, − and so on and are considered applicable for flexible films. Though manipulating surface charges has proven effective in mitigating flashover, the underlying mechanisms remain elusive.…”

Section: Introductionmentioning

confidence: 99%

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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Two-Phase-Interfaced, Graded-Permittivity Titania Electrical Insulation by Atmospheric Pressure Plasmas

Cited by 32 publications

References 67 publications

High Performance Epoxy Composites Containing Nanofiller Modified by Plasma Bubbles

High Performance Epoxy Composites Containing Nanofiller Modified by Plasma Bubbles

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

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

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