Simultaneously Enhanced Thermal Conductivity and Dielectric Breakdown Strength in Sandwich AlN/Epoxy Composites.

Zhengdong Wang,Juan Wang,Jieyu He,Tong Zhang,Xiaozhuo Wang,Silong Wang,Guanglei Wu

doi:10.3390/nano11081898

Zhengdong Wang, Juan Wang + Show 5 more

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https://doi.org/10.3390/nano11081898

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Abstract

Polymer-based composites with high thermal conductivity and dielectric breakdown strength have gained increasing attention due to their significant application potential in both power electronic devices and power equipment. In this study, we successfully prepared novel sandwich AlN/epoxy composites with various layer thicknesses, showing simultaneously and remarkably enhanced dielectric breakdown strength and thermal conductivity. The most optimized sandwich composite, with an outer layer thickness of 120 μm and an inner layer thickness of 60 μm (abbreviated as 120-60) exhibits a high through-plane thermal conductivity of 0.754 W/(m·K) (4.1 times of epoxy) and has a dielectric breakdown strength of 69.7 kV/mm, 8.1% higher compared to that of epoxy. The sandwich composites also have higher in-plane thermal conductivity (1.88 W/(m·K) for 120-60) based on the novel parallel models. The sandwich composites with desirable thermal and electrical properties are very promising for application in power electronic devices and power equipment.

Highlights

Along with their rapid development within the electronic and electrical industry, high dielectric breakdown strength materials have attracted increasing attention due to their potential application in high-voltage equipment and power electronic devices with high power density [1,2,3,4]
The results showed that the sandwiched composites have a higher dielectric breakdown strength and thermal conductivity due to electric field redistribution and the barrier effect, as a result of a changes in the initial breakdown conditions
The dielectric breakdown strength of the epoxy composites with micro-fillers shows an obvious decrease in comparison with that of neat epoxy

Summary

Introduction

Along with their rapid development within the electronic and electrical industry, high dielectric breakdown strength materials have attracted increasing attention due to their potential application in high-voltage equipment and power electronic devices with high power density (e.g., insulated gate bipolar transistor) [1,2,3,4]. It is worth noting that these devices and equipment tend to be manufactured with high miniaturization and integration to improve performance, which leads to an increased threat from the high heat dissipation and electric field strength [10,11,12]. High thermal conductivity and dielectric breakdown strength polymer composites are, highly needed as dielectric materials for energy storage, power electronic devices, and power equipment to enhance heat conduction and the tolerance on electric field [13,14]. The low thermal conductivity of neat epoxy resin cannot meet the requirements of power electronics and equipment [18,19]

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Results

Conclusion