Classification and application of thermal silica gel
Thermal silica gel can be divided into three states: grease, paste and patch.
Thermally conductive silicone grease has the highest thermal conductivity among the three thermally conductive silicones. Thermally conductive silicone grease is paste-like, sticky and non-drying. Generally, it can be used for more than five years. Thermally conductive silicone grease is mainly used to fill the gap between the CPU and the heat sink. This material is also called thermal interface material. Its function is to transfer the heat emitted by the CPU to the heat sink, keep the CPU temperature at a stable working level, prevent the CPU from being damaged due to poor heat dissipation, and extend its service life. Because in the application of heat sinks and heat-conducting devices, even two flat surfaces with very smooth surfaces will have gaps when they contact each other. The air in these gaps is a poor heat conduction medium, which will hinder the conduction of heat to the heat sink. Thermally conductive silicone grease is a material that can fill these gaps and make the heat conduction smoother and faster.
Thermally conductive paste is a thermal interface material. Thermally conductive silicone is thermally conductive RTV glue. It can be cured at room temperature. The color is white or black. It needs to react with water vapor in the air to cure. The biggest difference between thermal conductive paste and thermal conductive silicone grease That is, the thermal paste can be cured, and it has a certain degree of elasticity, adhesiveness and extensibility after curing. The thermal paste has fixing and bonding properties, so it meets the general process sealing. The thermal conductivity of the thermal paste is the lowest among the three types of silica gel. It is suitable for the thermal conductivity of capacitors and resistors and the bonding between some heating components. It has strong acid and alkali resistance, but the working temperature of the thermal paste is average. Does not exceed 200°C.
When used in large-area heat dissipation such as power supplies in industry, a thermally conductive patch is needed because the cost of thermally conductive patch is low, it is non-drying, easy to replace, thermal conductivity is generally low, and the high temperature can reach 300 ℃, the low temperature is generally -60℃. In electronic products, it is generally used on the surface of some electronic parts and chips that generate less heat but are not easy to dissipate. It is suitable for simple processing of ordinary devices. A thermal conductive patch is generally attached to the side of a better battery. While conducting heat, it can fill the gap between the battery and the casing, and play a buffering and stable role. The thermal conductivity of this material is relatively small, so it is not suitable for high-end electronic products (such as computer CPU).