石墨烯散熱塗料於LED性能提升之技術開發
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2019
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近年來，電子產品朝向講求輕薄短小、追求多功能及效能更高的趨勢發展，而多功和效能的提高也產生更高耗電量與廢熱的問題。一般工業設備大都會在熱源或散熱鰭片部位安裝風扇進行主動式冷卻散熱，而部分電子產品，如LED照明燈具因受到幾何結構或尺寸限制，無法加裝主動式散熱系統，只能依賴金屬散熱片等被動散熱裝置，利用金屬的高導熱係數，以熱傳導將熱由熱源導出至散熱鰭片，達到降溫的效果。不過金屬表面的熱輻射係數(Emissivity)極低，匯集到散熱鰭片的熱不易發散至環境中。因此，如何提高金屬表面之熱輻射係數，已成為極待解決的問題。本研究預計開發出一種散熱塗料(Heat dissipation coating)，以油性環氧樹脂作為基底，添加擁有高熱輻射性能之奈米碳材與良好熱傳導係數之氮化鋁顆粒，調整填充物的比例與塗料黏度後，塗佈一具有高熱輻射係數且低熱阻之散熱薄膜於金屬散熱片表面，提升其被動散熱的效果，並利用大氣電漿(Atmospheric pressure plasma, APP) 與硫酸對奈米碳材進行官能化改質處理，進一步提升塗料之熱輻射性能。本研究添加化學官能化改質的奈米碳材，使用比例為10 wt%氮化鋁、2 wt%石墨烯與2 wt%多壁奈米碳管，以真空脫泡攪拌機混拌後於散熱鋁片進行 20 μm 之薄膜塗佈。使用紅外線熱像儀量測其熱輻射係數可達0.98，應用於9W LED之降溫測試，可使LED降溫15.3 ℃，並提升8%之流明值。再透過熱重分析儀(Thermogravimetric analysis, TGA)測試，該散熱塗料之熱分解溫度達311 ℃，表示本研究所製備之散熱塗料在實際應用上也具有良好的穩定性。
In recent years, electronic products have been trending toward the trend of being light and thin, pursuing versatility and higher performance, and the improvement of performance has also caused problems of higher power consumption and waste heat generation. Generally, industrial equipment always installs a fan on the heat sink to achieve heat dissipation so-called active cooling. However, some electronic products, such as LED lighting fixtures, cannot be equipped with an active cooling system due to geometrical or size limitation. They can only rely on passive cooling such as metal heat sinks, using the high thermal conductivity of the metal, heat is transferred from the heat source to the heat sink fins by heat conduction. However, the emissivity of the metal surface is extremely low, and the heat collected in the heat sink can not easily dissipated into the environment. Therefore, how to improve the emissivity of the metal surface has become an problem to be solved. In this study, we developed a heat dissipation coating with an oil-based epoxy resin as the polymer matrix. Adding nanocarbon materials withhigh thermal radiation property and good thermal conductivity of aluminum nitride particles, coating a heat-dissipation film with high thermal emissivity on the surface of the metal heat sink to enhance the passive heat dissipation effect. Atmospheric pressure plasma (APP) and sulfuric acid are used to functionalize the nanocarbon materials to further improve the thermal radiation performance of the coating. Using the chemically functionalized nanocarbon materials of this study, an optimal ratio of 10 wt% aluminum nitride, 2 wt% graphene and 2 wt% multi-walled carbon nanotubes heat-dissipation coating was applied to the aluminum heat sink with 20 μm film thickness. The emissivity measured by an infrared camera can reach 0.98. It can be used to cool the 9W LED of 15.3 °C and increase the lumen value by 8%. The thermal decomposition temperature of the heat-dissipation coating reached 311 °C through the thermogravimetric analysis (TGA) test, indicating that the heat-dissipation coatings prepared in this study also has good stability in practical applications.
In recent years, electronic products have been trending toward the trend of being light and thin, pursuing versatility and higher performance, and the improvement of performance has also caused problems of higher power consumption and waste heat generation. Generally, industrial equipment always installs a fan on the heat sink to achieve heat dissipation so-called active cooling. However, some electronic products, such as LED lighting fixtures, cannot be equipped with an active cooling system due to geometrical or size limitation. They can only rely on passive cooling such as metal heat sinks, using the high thermal conductivity of the metal, heat is transferred from the heat source to the heat sink fins by heat conduction. However, the emissivity of the metal surface is extremely low, and the heat collected in the heat sink can not easily dissipated into the environment. Therefore, how to improve the emissivity of the metal surface has become an problem to be solved. In this study, we developed a heat dissipation coating with an oil-based epoxy resin as the polymer matrix. Adding nanocarbon materials withhigh thermal radiation property and good thermal conductivity of aluminum nitride particles, coating a heat-dissipation film with high thermal emissivity on the surface of the metal heat sink to enhance the passive heat dissipation effect. Atmospheric pressure plasma (APP) and sulfuric acid are used to functionalize the nanocarbon materials to further improve the thermal radiation performance of the coating. Using the chemically functionalized nanocarbon materials of this study, an optimal ratio of 10 wt% aluminum nitride, 2 wt% graphene and 2 wt% multi-walled carbon nanotubes heat-dissipation coating was applied to the aluminum heat sink with 20 μm film thickness. The emissivity measured by an infrared camera can reach 0.98. It can be used to cool the 9W LED of 15.3 °C and increase the lumen value by 8%. The thermal decomposition temperature of the heat-dissipation coating reached 311 °C through the thermogravimetric analysis (TGA) test, indicating that the heat-dissipation coatings prepared in this study also has good stability in practical applications.
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石墨烯, 奈米碳管, 散熱塗料, 環氧樹脂, 熱輻射係數, graphene, carbon nanotubes, heat-dissipaton coatings, epoxy, emissivity, LED