Deposition of SiC_xH_yO_zthin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

Abstract

Non-thermal plasma surface modification for epoxy resin (EP) to improve the insulation properties has wide application prospects in gas insulated switchgear and gas insulated transmission line. In this paper, a pulsed Ar dual dielectrics atmospheric-pressure plasma jet (APPJ) was used for SiC x H y O z thin film deposition on EP samples. The film deposition was optimized by varying the treatment time while other parameters were kept at constants (treatment distance: 10 mm, precursor flow rate: 0.6 l min −1 , maximum instantaneous power: 3.08 kW and single pulse energy: 0.18 mJ). It was found that the maximum value of flashover voltages for negative and positive voltage were improved by 18% and 13% when the deposition time was 3 min, respectively. The flashover voltage reduced as treatment time increased. Moreover, all the surface conductivity, surface charge dissipation rate and surface trap level distribution reached an optimal value when thin film deposition time was 3 min. Other measurements, such as atomic force microscopy and scanning electron microscope for EP surface morphology, Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy for EP surface compositions, optical emission spectra for APPJ deposition process were carried out to better understand the deposition processes and mechanisms. The results indicated that the original organic groups (C-H, CC , C=O, C=C) were gradually replaced by the Si containing inorganic groups (Si-O-Si and Si-OH). The reduction of C=O in ester group and C=C in p-substituted benzene of the EP samples might be responsible for shallowing the trap level and then enhancing the flashover voltage. However, when the plasma treatment time was longer than 3 min, the significant increase of the surface roughness might increase the trap level depth and then deteriorate the flashover performance.

Micro-Structure and Thermomechanical Properties of Crosslinked Epoxy Composite Modified by Nano-SiO2: A Molecular Dynamics Simulation

“…With the growing expansion of electrical equipment applications, the disadvantages of the Epoxy Resin (EP) insulating materials such as Diglycidyl Ether of Bisphenol A resin/Methyltetrahydrophthalic Anhydride (DGEBA/MTHPA) have become increasingly obvious. Some of the properties, including mechanical and thermal properties, are often not able to meet the ever-increasing requirements of electrical equipment [1,2,3,4]; while, the emergence of nanomaterials and the development of nanotechnology in recent years have provided new ways to improve the comprehensive properties of EP [5,6]. Compared with traditional materials, the distinguishing structure of nanomaterial has provided a set of unique features, such as the small size effect, quantum size effect and surface effect [7,8], which further enhance the performance in various aspects of physics and chemistry.…”

Review of interface tailoring techniques and applications to improve insulation performance

“…Due to the mild reaction conditions, PECVD is more frequently employed in surface deposition to improve various properties such as flashover strength, breakdown voltage and hydrophobicity. Abbasi-Firouzjah et al, Shao et al and Xie et al used tetraethoxysilane as the precursor in plasma treatment to build SiO x thin films on the substrate, which increased the surface conductivity and flashover voltage [24,66,67]. Due to the broad bandgap of SiO 2 , a similar method was adopted by Li et al to raise the injection barrier at the electrode-dielectric interface, which consequently improved breakdown strength and energy density [20].…”

Improvement of surface flashover in vacuum

“…However, such plasma source can only be applied to flat and thin materials, and sometimes discharge filaments in the DBD may damage the material surface. In recent years, the atmospheric pressure plasma jet (APPJ) has been attracting great attention as a new plasma source, which provides uniform spatial distributions of high energy ions and electrons to treat complex surfaces of materials [76,83,84]. There are some experimental results of plasma treatment on insulator surfaces in Table 3, which indicates surface flashover in vacuum can be improved by DBD or APPJ method [76,[81][82][83][84].…”