Thermal Radiative Copper Oxide Layer for Enhancing Heat Dissipation of Metal Surface

Junghyun Park,Junghoon Lee,Donghyun Kim,Wonsub Chung,Hyunsik Kim

doi:10.3390/nano11112819

Abstract

The heat dissipation of a metal heat sink for passive cooling can be enhanced by surface modifications to increase its thermal emissivity, which is reflected by a darker surface appearance. In this study, copper electrodeposition followed by heat treatment was applied to a copper substrate. The heat treatment formed a nanoporous oxide layer containing CuO and Cu2O, which has a dark blackish color and therefore increased the thermal emissivity of the surface. The heat dissipation performance was evaluated using the sample as a heat sink for an LED module. The surface-treated copper heat sink with a high thermal emissivity oxide layer enhanced the heat dissipation of the LED module and allowed it to be operated at a lower temperature. With an increase in the heat treatment, the thermal emissivity increases to 0.865, but the thermal diffusivity is lower than the copper substrate by ~12%. These results indicate that the oxide layer is a thermal barrier for heat transfer, thus optimization between the oxide thickness and thermal emissivity is required by evaluating heat dissipation performance in operating conditions. In this study, an oxide layer with an emissivity of 0.857 and ~5% lower thermal diffusivity than the copper substrate showed the lowest LED operating temperature.

Highlights

Because CuO and Cu2 O have higher emissivity than Cu metal, the formation of copper oxides on the copper surface can be identified from the surface appearance
As the heat-treatment duration increased, the surfaces became darker in color (Figure 1a), which indicates that oxides were formed during the heat treatment
The volume of the copper layer expands to become an oxide layer, the sharp crystal structure formed by electrodeposition collapses to become an agglomerated nanospherical particle structure

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Thermal (or heat) management is essential for stable performance and lifetimes in various engineering systems. The design of an engineering system requires consideration of its heat dissipation, which refers to the release of heat generated during the operation of the system to the external environment. Thermal management with engineering systems and materials is important in collecting solar energy and its conversion [1,2,3]. Similar to various systems that generate heat, heat dissipation is a critical issue affecting the performance of integrated light-emitting diode (LED) systems [4,5,6,7,8]

Methods

Results

Conclusion