| Thermal spray coating processes have been employed to create either copper wicks or zinc skins of the heat spreaders that were designed for LEDs cooling application. Two copper coating samples and two polymer coating samples were made using flame spray and wire-arc spray, respectively. The microstructural characteristics and the capillary effects of coating samples were studied. To study the heat transfer characteristics, two test chambers featured copper and polymer coating samples and filled with distilled water and ethanol were tested. Two composite heat spreaders featuring the zinc skins and the porous polymer wicks were created. The best thermal performance in terms of the lowest overall thermal resistance of 3.72 cm2·K/W was achieved by the cylindrical composite heat spreader with the ethanol at a charge ratio of 51.5%. The rectangular composite has an overall thermal resistance of 4.81 cm2·K/W with the water at a charge ratio of 53.7%. |
