As the most representative heat-conducting silica gel sheet in heat-conducting materials, it is mainly made of organic silica gel and has certain ductility. It can well fill the gap between the heating element and the heat sink, remove the air on the uneven surface, and form a good heat flow channel.
What kind of thermal silica gel sheet can be called good? What aspects should we start with when investigating a thermal silica gel sheet?
1. Thermal conductivity
This is a factor that everyone is most concerned about. Thermal conductivity refers to the heat transfer through an area of 1 square meter in 1 hour for a material with a thickness of 1m and a temperature difference of 1 degree (K, ℃) between the two sides of the material under stable heat transfer conditions. The higher the thermal conductivity of the thermally conductive silicone sheet, the faster it can transfer the heat from the electronic components to the radiator, and the better the thermal conductivity.
2. Hardness selection
Shore hardness is generally used to measure the hardness of heat-conducting materials. The test principle is to drop a specified diamond punch from a fixed height on the surface of the sample, the punch bounces to a certain height, and the ratio of the bounce height to the drop height is used to calculate the Shore hardness.
The heat-conducting silicone sheet has low hardness, soft hand feeling, and certain ductility, which can better fit the interface gap of the component and achieve a more ideal heat transfer effect; if the hardness of the silicone sheet is too high, the gap cannot be effectively filled, and the efficiency of heat flow passing will also be reduced.
However, the smaller the hardness ≠ the better the heat conduction effect. If the hardness of the heat conduction silicone sheet is too low, deformation and tearing will occur during the product installation process. In order to avoid this situation, some powerful and experienced manufacturers, such as TENSAN, under the premise of meeting the heat conduction requirements, will reinforce the thermally conductive silica gel sheet to enhance the toughness of the silica gel sheet.
3. Thickness selection
The silicone material has a certain anti-compression performance, which can effectively reduce the transmission distance of heat flow by enhancing the fit of the silicone sheet through compression. The thickness of the silicone sheet should be selected according to the specific components.
4. Specific gravity
The porosity of various thermal insulation materials is usually very high, relatively speaking, their specific gravity is also very low; on the contrary, the silica gel sheet as a heat-conducting material, the greater the porosity, the heat transfer performance of the heat-conducting material will be greatly reduced.
