Abstract
To prepare high-permittivity composite materials for dielectrically functional gradient materials (d-FGMs) by the stereolithographic 3D-printing technique, three ceramic powders (i.e., alumina, barium titanate, and strontium titanate) are selected as functional fillers for a UV-curable resin matrix. The viscosity and UV curing depth of the uncured slurry are tested for feasibility of 3D printing. Comprehensive electrical properties, including volume resistivity, permittivity, dielectric loss, and breakdown strength of the cured composites are measured. The effects of the filler types, morphologies, particle sizes, and volume fractions on the UV curing characteristics of the slurry and dielectric properties of cured composites are systematically analyzed. The experimental results show that spherical fillers with large particle sizes, smooth surfaces, and high permittivity are conducive for reducing the slurry viscosity, increasing curing depth and adjusting the composite’s permittivity over a wide range. We believe that the proposed strategy for material system establishment can improve the 3D printability of high-permittivity composites and promote other applications of the d-FGMs by the stereolithography technique.
Highlights
High-voltage power equipment requires strong insulation systems [1]
By controlling the permittivity or electrical conductivity distribution of the composite, the electric field can be actively controlled to alleviate distortions and formation of local regions; such insulation structures could be summarized as dielectrically functional gradient materials (d-FGMs) [9, 10]
We investigate the influence of the filler type, morphology, particle size, and filling content on the dielectric properties of composites and related properties in order to provide a good selection for the preparation of ε-FGM insulators by Stereo Lithography Apparatus (SLA) technology
Summary
High-voltage power equipment requires strong insulation systems [1]. their breakdown caused by distorted electric fields is a widespread engineering problem. By controlling the permittivity or electrical conductivity distribution of the composite, the electric field can be actively controlled to alleviate distortions and formation of local regions; such insulation structures could be summarized as dielectrically functional gradient materials (d-FGMs) [9, 10]. For the purpose of maintaining the stability of the viscosity of the slurry along the gradient direction to reduce the difficulty of printing and avoiding a major impact on its dielectric properties, we would like to build a double-filler system, so choose alumina with different sizes (~40 μm and~4 μm) and low intrinsic permittivity (εr = 10) as another filler, which has good light transmittance, high thermal conductivity, low loss, etc. We investigate the influence of the filler type, morphology, particle size, and filling content on the dielectric properties of composites and related properties (viscosity and UV curing depth) in order to provide a good selection for the preparation of ε-FGM insulators by SLA technology.
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