Thermally conductive silicone is mainly used in the heat conduction and heat dissipation function of heat-generating components. The performance of ordinary thermally conductive silicone depends on the aluminum hydroxide component incorporated into it. Of course, special thermally conductive silicone grease will incorporate an appropriate amount of precious metal oxides. It is mainly composed of four components: polydimethylsiloxane, aluminum hydroxide, quartz powder, methyltrimethoxysilane, and chelated titanium.
Thermally conductive silica gel can be divided into three states: grease, paste and patch according to its use.
Thermal grease is the one with the highest thermal conductivity among the three types of thermal conductive silicone. Thermal 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 conduct the heat emitted by the CPU to the heat sink, keep the temperature of the CPU at a level that can work stably, prevent the CPU from being damaged due to poor heat dissipation, and prolong its service life. Because in the application of heat sinks and thermally conductive devices, even two planes with very smooth surfaces will have gaps when they are in contact with each other. The air in these gaps is a poor medium for heat conduction, which will hinder the conduction of heat to the heat sink. Thermal grease is a material that can fill these voids, making heat conduction smoother and faster.
Thermal paste is a thermal interface material. Thermally conductive silicone is a thermally conductive RTV adhesive. It is a colloid that can be cured at room temperature. The color is white or black. It needs to react with the water vapor in the air before curing. That is, the thermal conductive paste can be cured. After curing, it has certain elasticity, adhesion and extensibility. The thermal conductive paste has fixed and adhesive properties, so it is in line with general process sealing. The thermal conductivity of the thermal paste is the lowest among the three types of silica gels. It is suitable for the heat conduction of components such as capacitors and resistors, as well as the bonding between some heating components. It has strong acid and alkali resistance, but the working temperature of the thermal paste is average. not exceed 200°C.
When it is used for large-area heat dissipation such as power supply in industry, the material of thermal conductive patch is needed, because the cost of thermal conductive patch is low, it has non-drying properties, it is easy to replace, the thermal conductivity is generally low, and the high temperature can reach 300 °C, and the low temperature is generally -60 °C. In electronic products, it is generally used on the surface of some electronic parts and chips that generate less heat but is not easy to dissipate heat. It is suitable for simple processing of ordinary devices. On the side of better batteries, thermal conductive patches are usually attached. 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 CPUs).