As a representative heat-conducting silica gel sheet among heat-conducting materials, it is mainly made of organic silica gel and has a certain degree of ductility. It can well fill the gap between the heating element and the heat sink, remove the air from the uneven surface, and form a good heat flow channel.

What kind of thermal silica gel sheet is good? What aspects should we start with when investigating thermal silica gel sheets?

1. Thermal conductivity

Thermal conductivity refers to the heat transfer through an area of 1 square meter within 1 hour for a material with a thickness of 1m and a temperature difference of 1 degree (K, °C) on both sides under stable heat transfer conditions, the unit is W/ Meter degrees (W/(m K), where K can be replaced by °C. The higher the thermal conductivity of the thermally conductive silicone sheet, the faster it transfers the heat from the electronic components to the radiator, and the better the thermal conductivity.

2. Hardness selection

Shore hardness is usually used for the hardness of thermally conductive materials. The test principle is to drop the specified diamond punch from a fixed height to the surface of the sample, then the punch bounces to a certain height, and calculate the Shore hardness by the ratio of the bounce height to the drop height.

The thermally conductive silicone sheet has low hardness, soft hand feeling, and certain ductility, which can better fit the gap of the component interface and achieve a more ideal heat transfer effect; if the hardness of the silicone sheet is too high, it cannot effectively fill the gap, and the corresponding Therefore, the efficiency of heat flow will also be reduced.

However, the smaller the hardness ≠ the better the thermal conductivity. The hardness of the thermal silicone sheet is too low, and it may be deformed and torn during product installation. In order to avoid this situation, some large and experienced manufacturers will reinforce the thermally conductive silicone sheet to enhance the toughness of the silicone sheet on the premise of meeting the thermal conductivity requirements.

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 determined according to the specific components.

4. Specific gravity

The porosity of various thermal insulation materials is usually high, and relatively speaking, their specific gravity is also very low. On the contrary, the greater the porosity of the silica gel sheet used as a heat-conducting material, the greater the heat transfer performance of the heat-conducting material will be greatly reduced.

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