Some "220V Cooling Fan" heatsink uses a combination of copper and aluminum to manufacture. The heat sink base mostly copper, and the metal fins are made of aluminum. Thermal conductivity higher than aluminum and copper, can be more uniformly transfer heat to the aluminum fins of the periphery. The thermal conductivity of aluminum itself is not infinitely large, there is a temperature gradient inside fins: the higher the temperature near the center fin assembly, close to the periphery around the lower temperature. It is worth noting that an important factor is the heat conduction temperature gradients exist. "220V Cooling Fan" fin central section has a high thermal conductivity effect, the effect will have around badly, thus leading to lower overall thermal conduction effect. Use of copper chip solution the problem of uneven temperature gradient, although an increase in thermal resistance, but it greatly improves the uniform distribution of temperature of the entire fin, can be said to be still larger than the loss. In the following table, we give some of the common heat transfer coefficient of metal material. Because "220V Cooling Fan" radiator material impact on the overall cooling effect is very large, so each product selection of the material has become the focus of attention on the topic.