The thermal conductivity of heat sink material is different. According to the thermal conductivity, the best material is silver, followed by copper, aluminum, and steel successively. Silver is too expensive, so we usually choose copper and aluminum alloy as heat sink material, either of which has its own advantages and disadvantages.
Thermal conductivity of copper is good, almost twice as much as that of aluminum, but its more expensive, weighty and easily being oxidized and has more difficulties in processing and smaller thermal capacity. The most commonly used material is aluminum. Pure aluminum is not used in heat sinks, because it is too soft and can not provide enough hardness. We usually use aluminum alloys.
Thermal conductivity values depend on the temper of the alloy. Compared with copper, aluminum is much cheaper and lighter. Another advantage is that it can be extruded, but copper can not. Radiative cooling may not be an important factor, but in some situations in which convection is very low, the surface color can be an important factor.
Shiny bare metal can not radiate as efficiently as matte black surface because of its low emissivity, while matte black has high emissivity, so it can radiate radiant efficiently. Anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of mental parts. Anodizing increases corrosion resistance and wear resistance, and provides better adhesion of paint primers and glues than bare metal does. Anodization changes the microscopic texture of the surface and changes the crystal structure of the metal near the surface. For example, anodized aluminum surfaces are harder than aluminum but have low to moderate wear resistance that can be improved by increasing thickness or by applying suitable sealing substances.When pure aluminum is exposed to air at room temperature or any other gas containing oxygen, it can self-passivate by forming a surface layer of amorphous aluminum oxide 2 to 3 nm thick, which can protect aluminum from being corroded effectively. Compared with pure aluminum, aluminum alloys can form a thicker oxide layer, but it is also more easily being affected by corrosion. We can increase the anodized aluminum surfaces thickness of this layer for corrosion resistance. Length: 105mm (4.1 inch) Width: 66.2mm (2.6 inch) Heigth: 30mm (1.18 inch) Weight: 0.245kg (8.6 oz) Color: black Material: aluminum. Please contact your local post office for missing or damaged package.
We are committed to your 100% satisfaction. We will do our best to help you within the shortest time. We have made tens of thousands customers happy world wide, otherwise, we would have not been in business for 20 years. The item "New Heat sink aluminum material and the surface black anodized with 4 holes" is in sale since Monday, June 16, 2014.
This item is in the category "Business & Industrial\Electrical Equipment & Supplies\Electronic Components & Semiconductors\Thermal Management\Heat Sinks". The seller is "analogtechnology" and is located in San Jose, California.This item can be shipped to United States.