Generally, we choose metal as the heat sink material and evaluate it according to the high specific heat ans thermal conductivity. We have introduced in the last article that silver and copper is the best thermal materials, followed by gold and aluminum. But gold, silver is rarely used at radiator production, because they have are too expensive. And copper and aluminum cost are much lower. Therefore radiator basically to be made by aluminum with copper.
Aluminium includes aluminium alloy. Copper and aluminium also are not perfect, have its advantage and disadvantage each. The conductivity of copper is good, but the price is expensive, difficultly to process, weight heave. and copper low heat capacity, and easy oxidation. And pure aluminium is opposite relatively soft do not have bearing capacity, the proportion that USES aluminium alloy is more. Aluminium alloy can offer enough hardness, have an advantage is the price is low, weight is light, but thermal conductivity is much lower than copper.
 | Pure aluminium heat sink |
Pure aluminum heat sink is more common, the manufacturing process is relatively simple and easy, low cost, because pure aluminum thermal conductivity is good, pure aluminum heat sink occupies more market share. Pure aluminum heat sink add fin to increase the heat dissipation area. The common processing method of pure aluminum radiator is aluminum extrusion technology. The main index of pure aluminum radiator heat dissipation performance parameters is the thickness of the radiator base and pin-fin ratio. Pin refers to the Fin height, Fin refers to the distance between two adjacent fins. The pin-fin ratio is the height of Pin (not including the thickness of the base) divided by Fin. The larger pin-fin ratio means the larger effective heat dissipation area of the radiator and the more advanced aluminum extrusion technology.
| Pure copper radiator |
Looking back on the previous article, we can see that copper has a thermal conductivity 1.69 times of aluminum, so under the same conditions, pure copper radiators can remove heat from the heat source faster. In the classification of copper, copper containing more than 99% is called anaerobic copper, the next grade of copper is red copper, containing less than 85%, followed by brass. Most of the copper radiator on the market is the use of red copper, copper also has obvious shortcomings, higher cost, high processing difficulty, heave weight, it hinder the application of pure copper heat sink.
| Copper-aluminum heat sink |
Through the comparison of the defects of copper and aluminum, some thermal design engineers recommend the way of combining copper and aluminum. Some high-end radiators often adopt the manufacturing process of combining copper and aluminum. These radiators usually adopt the copper base, while the heat dissipation fins adopt aluminum alloy.In addition to the use of copper heat pipe buried in the aluminum radiator bottom plate. A variety of different copper and aluminum combination, porvide various choice of radiator material and process. For different cooling function requirements of the product, is also a benefit. Aluminum radiator experts said, in the future there will be more ways to combine copper and aluminum, especially with the improvement of welding technology, copper and aluminum welding will be more and more mature.