Heat sinks are widely used for cooling electronic devices and LED lights, etc. Heat sinks without fans are preferred especially for mini-sized devices due to their compact size without noises or the need for power. Under these circumstances, natural convection and radiation are main means to dissipate the generated heat. Thus, enhancing radiation heat transfer becomes important. In this paper, a high-emissivity coating (ε = 0.934) with additives of carbon materials and SiO₂ was put on the surface of an aluminum heat sink. Experiments and simulations were performed to study the influence of the high-emissivity coating on the heat transfer performance. It is proved that the high-emissivity coating effectively reduces the equilibrium temperature of the heat sink. In experiments, the maximum temperature difference between the heat sink (base size: 100*60 mm) with and without coating reached 26 °C at a heating power of 18 W. The simulation results showed that radiation with coating greatly contributed to heat transfer and occupied 38% of the total dissipated power. The coating increased the total heat transfer coefficient by 23% and decreased thermal resistance by 18%. The heat sink partly coated on outer surfaces remains good thermal properties and could reduce the coating cost. In conclusion, the high-emissivity coating enhances heat transfer of passive heat sinks and has a promising prospect as an excellent thermal management material.

散热器广泛用于冷却电子设备和LED灯等。不带风扇的散热器特别适合于小型设备，这是因为它们的尺寸紧凑，无噪音或无需电源。在这种情况下，自然对流和辐射是消散产生的热量的主要手段。因此，增强辐射热传递变得重要。在本文中，采用 碳材料和SiO ₂添加剂的高发射率涂层（ε = 0.934）被放置在铝散热器的表面上。进行实验和模拟以研究高发射率涂层对传热性能的影响。事实证明，高发射率涂层有效降低了散热器的平衡温度。在实验中，在有和没有涂层的情况下，散热片（底座尺寸：100 * 60 mm）之间的最大温差在18 W的加热功率下达到26°C。仿真结果表明，带有涂层的辐射极大地促进了传热和散热。占总耗散功率的38％。涂层将总传热系数提高了23％，而耐热性降低了18％。部分涂覆在外表面上的散热器保持良好的热性能，并可以降低涂覆成本。综上所述，