Copper Aluminum Bonding Technology For Radiators

After considering the respective disadvantages of copper and aluminum materials, some high-end heat sinks in the market often use a copper aluminum combination manufacturing process. These heat sinks usually use copper metal bases, while the heat dissipation fins use aluminum alloys. Of course, in addition to the copper base, there are also methods such as using copper pillars for heat dissipation fins, which follow the same principle. With its high thermal conductivity, the copper bottom can quickly absorb the heat released by the CPU; Aluminum fins can be made into shapes that are most conducive to heat dissipation through complex manufacturing processes, providing a large heat storage space and rapid release, which has found a balance point in all aspects.
The dissipation of heat from the CPU core to the surface of the heat sink is a thermal conduction process. For the base of the heat sink, due to direct contact with a small area heat source with high heat, it is required that the base can quickly conduct heat away. Choosing materials with higher thermal conductivity for heat sinks is very helpful in improving thermal conductivity efficiency. From the comparison table of heat conduction systems, it can be seen that aluminum has a heat conduction coefficient of 237W/mK, while copper has a heat conduction coefficient of 401W/mK. Compared to heat sinks of the same volume, copper weighs three times more than aluminum, while aluminum has a specific heat of only 2.3 times that of copper. Therefore, under the same volume, copper heat sinks can hold more heat and heat up slower than aluminum heat sinks. A heat sink base of the same thickness, made of copper, can not only quickly dissipate the temperature of heat sources such as CPU Die, but also slow down its own temperature rise compared to aluminum heat sinks. Therefore, copper is more suitable for making the bottom surface of heat sinks.
However, the combination of these two metals is relatively difficult, and the affinity between copper and aluminum is poor. If the bonding process is not done well, a large interfacial thermal resistance (i.e., the thermal resistance between the two metals due to insufficient contact) will be generated. In practical design and manufacturing, manufacturers always try to minimize interface thermal resistance, highlight strengths and avoid weaknesses, which often reflects their design capabilities and manufacturing processes.